СТАЛЬ С ОЧЕНЬ ВЫСОКОЙ МЕХАНИЧЕСКОЙ ПРОЧНОСТЬЮ, СПОСОБ ПОЛУЧЕНИЯ ЛИСТА ИЗ СТАЛИ С ПОКРЫТИЕМ ИЗ ЦИНКАИЛИ ЦИНКОВОГО СПЛАВА И ЕГО ПРИМЕНЕНИЕ

Изобретение относится к металлургии, а именно к стали с очень высокой механической прочностью, листу, выполненному из такой стали, способу его получения, и может быть использовано в автомобильной промышленности. Сталь содержит, мас.%: 0,080≤С≤0,120, 0,800≤Mn≤0,950, Si≤0,300, Cr≤0,300, 0,150≤Mo≤0,350, 0, 020≤Al≤0,100, Р≤0,100, В≤0,010, Ti≤0,050, остальное - железо и примеси, образовавшиеся при выплавке, при этом микроструктура образована ферритом и мартенситом. Способ получения стального листа включает отливку листового слитка, горячую и холодную прокатки слитка для получения листа, нагрев листа со скоростью 2-100°С/с до температуры выдержки 700-900°С, охлаждение листа со скоростью 2-100°С/с до температуры, близкой к температуре ванны жидкого цинка или цинкового сплава, нанесение на лист покрытия из цинка или цинкового сплава погружением в указанную ванну и охлаждение до температуры окружающей среды со скоростью 2-100°С/с. Сталь имеет высокую прочность и способность к цинкованию. 4 н. и ...

СОСТАВ СВЕРХПРОЧНОЙ СТАЛИ, СПОСОБ ПОЛУЧЕНИЯ ИЗДЕЛИЯ ИЗ СВЕРХПРОЧНОЙ СТАЛИ И ПОЛУЧАЕМОЕ ИЗДЕЛИЕ

Изобретение относится к изделию из сверхпрочной стали и способу его получения. Изделие выполнено из сверхпрочной стали, содержащей, по меньшей мере, бейнитную фазу и/или мартенситную фазу, распределение фаз таково, что бейнитная и мартенситная фазы составляют в сумме более 35%. Способ получения изделия включает приготовление стального сляба, горячую прокатку указанного сляба, причем температура конца прокатки выше температуры Аr3, с образованием горячекатаной подложки, охлаждение до температуры смотки в рулон, смотку в рулон указанной подложки при температуре смотки от 450 до 750°С, травление указанной подложки с целью удаления оксидов. Согласно изобретению получают холоднокатаный и, в ряде случаев, горячеоцинкованный стальной лист с толщиной менее 1 мм и значениями предела прочности на растяжение 800-1600 МПа, тогда как удлинение А80 составляет от 5 до 17% в зависимости от параметров технологического процесса. Состав стали изделия подобран таким образом, что удается достичь высоких уровней ...

СТАЛЬ, ПРОДУКТ, ПРОИЗВЕДЕННЫЙ ИЗ ТАКОЙ СТАЛИ, И СПОСОБ ЕГО ИЗГОТОВЛЕНИЯ

Сталь, характеризующаяся тем, что ее состав, мас. %, представляет собой: 10,0≤Ni≤24,5; 1,0≤Mo≤12,0; 1,0≤Со≤25,0; 20,0≤Мо+Со+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≤29,0; Со+Мо≥20,0; Ni+Co+Mo≥29; следовые количества≤Al≤4,0; следовые количества≤Ti≤0,1; следовые количества≤N≤0,0050; следовые количества≤Si≤2,0; следовые количества≤Mn≤4,0; следовые количества≤C≤0,03; следовые количества≤S≤0,0020; следовые количества≤Р≤0,005; следовые количества≤В≤0,01; следовые количества≤Н≤0,0005; следовые количества≤О≤0,0025; следовые количества≤Cr≤5,0; следовые количества≤Cu≤2,0; следовые количества≤W≤4,0; следовые количества≤Zr≤4,0; следовые количества≤Ca≤0,1; следовые количества≤Mg≤0,1; следовые количества≤Nb≤4,0; следовые количества≤V≤4,0; следовые количества≤Ta≤4,0; остаток - железо и неизбежные примеси. Техническим результатом является изготовление стали с улучшенными механическими свойствами. 8 н. и 27 з.п. ф-лы, 3 ил., 7 табл.

ИЗДЕЛИЯ ИЗ ВЫСОКОПРОЧНОЙ СТАЛИ И СПОСОБЫ ИХ ИЗГОТОВЛЕНИЯ

Изобретение относится к изделиям из высокопрочной стали, обладающим благоприятными свойствами, и к способам отжига таких изделий. Способ термической обработки холоднокатаного листа из высокопрочной стали, содержащей, мас.%: от 0,12 до 0,5 С, от 1 до 3 Mn, от 0,8 до 3 комбинации Si и Al, включает проведение двухэтапного отжига листа. Первый этап отжига включает стадии, на первой из которых осуществляют нагрев листа до температуры от 820 до 980°С и выдержку в течение 20-500 сек, а на второй стадии - закалку при температуре ниже температуры окончания мартенситного превращения (MF) с последующим охлаждением ниже 300°С со скоростью, обеспечивающей формирование мартенситной структуры. Второй этап отжига включает стадии, на первой из которых осуществляют нагрев и томление при температуре от 720 до 850°С в течение 15-300 сек с последующим охлаждением до второй стадии, на которой при температуре от 360 до 440°С осуществляют выдержку в течение не более 800 сек. Формируемая при проведении двухэтапного ...

ВЫСОКОПРОЧНАЯ МНОГОФАЗНАЯ СТАЛЬ, СПОСОБ ЕЕ ПОЛУЧЕНИЯ И ПРИМЕНЕНИЕ

Изобретение относится к области металлургии. Для обеспечения предела прочности 980 МПа, предела текучести, более или равного 500 МПа, полного удлинения, превышающего или равного 8%, холоднокатаная листовая сталь содержит в мас.% 0,05≤С≤0,15, 2≤Mn≤3%, Al≤0,1, 0,3≤Si≤1,5, Nb≤0,05, N≤0,02, 0,1≤Cr+Mo≤1, 0,0001≤В≤0,0025, 3,4×N≤Ti≤0,5, V≤0,1, S≤0,01, P≤0,05, железо и неизбежные примеси - остальное, имеет микроструктуру в поверхностной фракции между 50 и 95% мартенсита и между 5 и 50% суммы феррита и бейнита, при этом размер ферритного зерна составляет менее 10 мкм и соотношение сторон ферритного зерна находится между 1 и 3. Сталь согласно изобретению окисляется, а затем восстанавливается при отжиге в ходе этапов нагревания, выдержки и охлаждения. 3 н. и 17 з.п. ф-лы, 1 ил. ,5 табл.

ЛИСТОВАЯ СТАЛЬ ДЛЯ ГОРЯЧЕГО ШТАМПОВАНИЯ И СПОСОБ ИЗГОТОВЛЕНИЯ ГОРЯЧЕШТАМПОВАННОЙ ДЕТАЛИ С ИСПОЛЬЗОВАНИЕМ ЛИСТОВОЙ СТАЛИ ДЛЯ ГОРЯЧЕГО ШТАМПОВАНИЯ

Изобретение относится к области металлургии, а именно к получению листовой стали для горячего штампования, используемой для изготовления горячештампованных деталей, обладающих высокой стойкостью к коррозии. На поверхность стальной основы нанесено последовательно два слоя: плакирующий слой I, содержащий 60 мас.% и более Ni и остальное Zn и неизбежные примеси, при этом масса покрытия находится в диапазоне от 0,01 до 5 г/м; и плакирующий слой II, содержащий от 10 до 25 мас.% Ni и остальное Zn и неизбежные примеси, при этом масса покрытия находится в диапазоне от 10 до 90 г/м. Достигается высокая стойкость к перфорирующей коррозии. 2 н. и 6 з.п. ф-лы, 3 табл., 2 пр.

СПОСОБ ИЗГОТОВЛЕНИЯ ЛИСТОВОЙ ТВИП-СТАЛИ, ВКЛЮЧАЮЩЕЙ АУСТЕНИТНУЮ МАТРИЦУ

Настоящее изобретение относится к способу производства листовой стали с пластичностью, наведенной двойникованием, имеющей аустенитную матрицу и используемой при изготовлении автомобильных транспортных средств. Сляб, содержащий при расчете на массу: 0,5 < C < 1,2%, 13,0 ≤ Mn < 25,0%, S ≤ 0,030%, P ≤ 0,080%, N ≤ 0,1%, Si ≤ 3,0%, 0,051% ≤ Al ≤ 4,0%, 0,1 ≤ V ≤ 2,5%, при необходимости один или несколько элементов из Nb ≤ 0,5%, B ≤ 0,005%, Cr ≤ 1,0%, Mo ≤ 0,40%, Ni ≤ 1,0%, Cu ≤ 5,0%, Ti ≤ 0,5% и 0,06 ≤ Sn ≤ 0,2%, остальное - железо и неизбежные примеси, повторно нагревают, осуществляют его горячую прокатку, скатывают в рулон, выполняют первую холодную прокатку, рекристаллизационный отжиг и вторую холодную прокатку. Обеспечивается получение листовой стали с высокими механическими свойствами. 2 н. и 21 з.п. ф-лы, 2 ил., 1 пр.

СПОСОБ ИЗГОТОВЛЕНИЯ ЛИСТА ИЗ ВЫСОКОПРОЧНОЙ СТАЛИ ПОСРЕДСТВОМ ГОРЯЧЕЙ И ХОЛОДНОЙ ПРОКАТКИ И ПОЛУЧАЕМЫЙ ЛИСТ

... 1. Способ изготовления листа из высокопрочной стали посредством горячей прокатки с последующей холодной прокаткой, имеющего предел прочности на растяжение не менее 450 МПа, включающий следующие этапы: высокопрочную сталь подвергают горячей прокатке для получения горячекатаного листа, затем вышеупомянутый горячекатаный лист подвергают холодной прокатке со степенью уменьшения толщины от 10 до 20%, затем подвергают прокатанный таким образом лист термической обработке восстановления при температуре ниже Ас3. 2. Способ по п.1, отличающийся тем, что высокопрочную сталь выбирают из многофазных сталей, сталей HLE микролегированных и сталей, легированных марганцем, с феррито-бейнитной структурой. 3. Способ по п.1 или 2, отличающийся тем, что вышеупомянутая высокопрочная сталь имеет предел прочности на растяжение σвр не менее 600 МПа. 4. Способ по п.3, отличающийся тем, что вышеупомянутая высокопрочная сталь имеет предел прочности на растяжение σвр не менее 800 МПа. 5. Способ по п.1, отличающийся ...

СПОСОБ ПОЛУЧЕНИЯ СТАЛИ, ИМЕЮЩЕЙ ДВУХФАЗНУЮ СТРУКТУРУ

... 1. Способ получения листа стали, имеющей зарождающуюся двухфазную микроструктуру, где указанный лист стали имеет состав, мас.%: углерод 0,02-0,20; алюминий 0,010-0,150; титан максимум 0,01; кремний максимум 0,5; фосфор максимум 0,060; сера максимум 0,030; марганец 1,5-2,40; хром 0,03-1,50; молибден 0,03-1, 50; при условии, что количества марганца, хрома и молибдена имеют соотношение (Mn+6Сr+10Мо) равно по меньшей мере 3,5%, включающий томление указанного листа стали в течение от 20 до 90 секунд при температуре в диапазоне от Ac1+25°C (45°F), но по меньшей мере 727°С (1340°F), но не более чем 775°С (1425°F), охлаждение указанного листа стали со скоростью по меньшей мере 1°С в секунду до температуры в диапазоне 454-493°С (850-920°F), и выдержку указанного листа стали в диапазоне 454-493°С (850-920°F) в течение от 20 до 100 с. 2. Способ по п.1, где указанный лист стали представляет собой стальную ленту, и указанный способ осуществляют непрерывно на стальной ленте длиной по меньшей мере 304,89 ...

ХОЛОДНОКАТАНЫЙ СТАЛЬНОЙ ЛИСТ И СПОСОБ ЕГО ПОЛУЧЕНИЯ

Изобретение относится к области металлургии, а именно к холоднокатаному стальному листу, используемому в автомобилестроении. Лист изготовлен из стали, содержащей в мас.%: С от 0,01 до 0,4, Si от 0,001 до 2,5, Mn от 0,001 до 4,0, Al от 0,001 до 2,0, P 0,15 или менее, S 0,03 или менее, N 0,01 или менее, O 0,01 или менее, Fe и неизбежные примеси остальное. Средняя полюсная плотность ориентационной группы от {100}<011> до {223}<110> составляет от 1,0 до 5,0, а полюсная плотность ориентации кристалла {332}<113> составляет от 1,0 до 4,0 на центральном участке толщины, в диапазоне толщины от 5/8 до 3/8 от основания поверхности стального листа. Величина rC Лэнкфорда в направлении, перпендикулярном направлению прокатки, составляет от 0,70 до 1,50, а величина r30 Лэнкфорда в направлении под углом 30° к направлению прокатки составляет от 0,70 до 1,50. Структура листа состоит из: от 30% до 99% феррит и бейнит, от 1% до 70% мартенсит. Обеспечиваются повышенные равномерная и локальная деформируемости ...

СТАЛЬНОЙ ПРОДУКТ СО СРЕДНИМ СОДЕРЖАНИЕМ МАРГАНЦА ДЛЯ ИСПОЛЬЗОВАНИЯ ПРИ НИЗКИХ ТЕМПЕРАТУРАХ И СПОСОБ ЕГО ПРОИЗВОДСТВА

Изобретение относится к области металлургии, а именно к стальному продукту, предназначенному для использования при низких температурах. Сталь продукта имеет следующий химический состав, вес.%: С от 0,01 до <0,3, Мn от 4 до <10, Аl от 0,003 до 2,9, Мо от 0,01 до 0,8, Si от 0,02 до 0,8, Ni от 0,005 до 3, Р<0,04, S<0,02, N<0,02, остальное железо и неизбежные примеси. Стальной продукт удовлетворяет одному из трех вариантов. В первом варианте сталь может содержать по меньшей мере один из следующих элементов, вес.%: Ti от 0,002 до 0,5; V от 0,006 до 0,1; Сr от 0,05 до 4; Сu от 0,05 до 2; Nb от 0,003 до 0,1; В от 0,0005 до 0,014; Со от 0,003 до 3; W от 0,03 до 2; Zr от 0,03 до 1; Са<0,004 и Sn<0,5, при этом выполняется условие 6<1,5Мn+Ni<8. Во втором варианте сталь может содержать по меньшей мере один из следующих элементов, вес.%: Ti от 0,002 до 0,5; V от 0,006 до 0,1; Сr от 0,05 до 4; Сu от 0,05 до 2; Nb от 0,003 до 0,1; В от 0,0005 до 0,014; Со от 0,003 до 3; W от 0,03 до 2; Zr от 0,03 до 1 ...

СПОСОБ ИЗГОТОВЛЕНИЯ ХОЛОДНОКАТАНОЙ СТАЛЬНОЙ ПОЛОСЫ ИЗ ВЫСОКОПРОЧНОЙ, СОДЕРЖАЩЕЙ МАРГАНЕЦ СТАЛИ С TRIP-СВОЙСТВАМИ

Изобретение относится к холоднокатаной стальной полосе, изготовленной из высокопрочной, содержащей марганец стали с TRIP-свойствами. Сталь содержит, вес.%: С: от 0,0005 до 0,9, Mn: от 3,0 до 12, при необходимости один или несколько из: Al: до 10, Si: до 6, Cr: до 6, Nb: до 1,5, V : до 1,5, Ti до 1,5, Мо: до 3, Cu: до 3, Sn: до 0,5, W: до 5, Co: до 8, Zr до 0,5, Та : до 0,5, Те до 0,5, B: до 0,15, Р: макс. 0,1, в частности < 0,04, S: макс. 0,1, в частности < 0,02, N: макс. 0,1, в частности < 0,05, и Са: до 0,1, железо и неизбежные примеси – остальное. Достигается повышение технологичности изготовления стальной полосы за счет обеспечения повышения степени деформации при прокатке. 4 н. и 22 з.п. ф-лы, 1 ил., 3 табл.

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СПОСОБ И СИСТЕМА ДЛЯ ОБРАБОТКИ ПОЛОСЫ ИЗ УГЛЕРОДИСТОЙ СТАЛИ, ПРЕЖДЕ ВСЕГО ДЛЯ ТРАВЛЕНИЯ

СПОСОБ И ПРОИЗВОДСТВЕННАЯ ЛИНИЯ ДЛЯ ПОЛУЧЕНИЯ ХОЛОДНОКАТАНОГО ПЛОСКОГО ИЗДЕЛИЯ ИЗ НЕРЖАВЕЮЩЕЙ СТАЛИ

... 1. Способ получения холоднокатаного плоского изделия (Е) из покрытой окалиной, состоящей из нержавеющей стали горячекатаной полосы (W), при котором покрытую окалиной горячекатаную полосу (W) подвергают холодной прокатке в стальное плоское изделие (Е), холоднокатаное стальное плоское изделия (Е) отжигают и удаляют с него окалину, отличающийся тем, что после холодной прокатки горячекатаной полосы (W) холоднокатаное стальное плоское изделие (Е) в наклепанном состоянии перед отжигом подвергают обработке по удалению окалины, при которой механически удаляют имеющуюся на холоднокатаном стальном плоском изделии (Е) окалину.2. Способ по п.1, отличающийся тем, что удаление окалины с холоднокатаного наклепанного стального плоского изделия (Е) осуществляют перед отжигом посредством струйной обработки твердыми частицами.3. Способ по п.1 или 2, отличающийся тем, что имеющиеся на холоднокатаном наклепанном стальном плоском изделии (Е) остатки жидкости перед удалением окалины удаляют посредством термообработки ...

СТАЛЬ ДЛЯ ГОРЯЧЕЙ ШТАМПОВКИ ИЛИ ЗАКАЛКИ В ИНСТРУМЕНТЕ, ОБЛАДАЮЩАЯ УЛУЧШЕННОЙ ПЛАСТИЧНОСТЬЮ

... 1. Стальная деталь из стали с содержанием, мас.%: ! 0,040≤С≤0,100; ! 0,80≤Mn≤2,00; ! Si≤0,30; ! S≤0,005; ! P≤0,030; ! 0,010≤Al≤0,070; ! 0,015≤Nb≤0,100; ! 0,030≤Ti≤0,080; ! N≤0,09; ! Cu≤0,100; ! Ni≤0,100; ! Cr≤0,100; ! Mo≤0,100; ! Са≤0,006, ! остальное: железо и неизбежные примеси, образующиеся в результате плавки, и микроструктура указанной стали состоит, по меньшей мере, из 75% равноосного феррита, мартенсита в количестве не менее 5%, но не более 20%, и бейнита в количестве не превышающем 10%. ! 2. Стальная деталь по п.1, отличающаяся содержанием в указанной стали, мас.%: ! 0,050≤С≤0,080; ! 1,20≤Mn≤1,70; ! Si≤0,070; ! S≤0,004; ! P≤0,020; ! 0,020≤Al≤0,040; ! 0,030≤Nb≤0,070; ! 0,060≤Ti≤0,080; ! N≤0,009; ! Cu≤0,100; ! Ni≤0,100; ! Cr≤0,100; !Mo≤0,100; ! Са≤0,005, ! остальное: железо и неизбежные примеси, образующиеся в результате плавки. ! 3. Стальная деталь по п.1 или 2, отличающаяся тем, что средний размер зерна феррита в структуре указанной стали составляет менее 6 мкм. ! 4. Стальная деталь ...

Antioxidans, Verfahren zur Verarbeitung von Stahlmaterial und nach dem Verfahren hergestelltes gewalztes Produkt

Die vorliegende Erfindung betrifft ein Antioxidans, ein Verfahren zur Verarbeitung eines Stahlmaterials und ein gewalztes Produkt, das unter Verwendung des gleichen Verfahrens hergestellt wird, wobei das Verfahren die folgenden Schritte umfasst: Herstellen eines Stahlmaterials; Herstellen eines Antioxidans; Aufbringen des Antioxidans auf die Oberfläche des Stahlmaterials, um einen Antioxidationsfilm durch Schmelzen zu bilden; und thermisches Behandeln des Stahlmaterials mit dem darauf gebildeten Antioxidationsfilm, wodurch die Korngrenzenoxidation an der Oberfläche des Stahlmaterials eingeschränkt werden kann, mit der resultierenden Verringerung von Oberflächendefekten in einem Endprodukt.

Feuerverzinktes Stahlblech und Verfahren zu dessen Herstellung

Producing steel element comprising zinc alloy coating, comprises stamping out blank from sheet metal coated with zinc alloy, heating stamped-out blank to temperature, and holding blank at this temperature for predetermined time

The method comprises stamping out a blank from a sheet metal coated with zinc or zinc alloy, heating the stamped-out blank in an oven to a temperature, holding the blank at this temperature for a predetermined time to allow the formation of austenite, cooling the blank at a temperature of 500-600[deg] C to achieve a solidification of a zinc layer, transferring the heated blank to a forming tool, forming a steel element in the forming tool, and cooling the blank in the tool at a cooling rate above the critical quenching rate to harden the blank. The method comprises stamping out a blank from a sheet metal coated with zinc or zinc alloy, heating the stamped-out blank in an oven to a temperature, holding the blank at this temperature for a predetermined time to allow the formation of austenite, cooling the blank at a temperature of 500-600[deg] C to achieve a solidification of a zinc layer, transferring the heated blank to a forming tool, forming a steel element in the forming tool, and cooling ...

A transmission chain

Aluminum-Plated Steel Sheets

A process for preparing molten- aluminium-plated steel sheets having good formability and high oxidation resistance at elevated temperatures comprises producing a steel containing 0.001-0.020% of C, 0.05-0.30% of Mn, 0.05-0.50% of Cr, 0.01-0.10% of Al, and 0.10-0.50% and not less than 10 times the C content of Ti, and making the steel into a hot coil with the coiling temperature not lower than 700 DEG C, cold-rolling said hot coil and plating the cold-rolled sheet by heating it to a temperature not lower than 850 DEG C using an in-line annealing type plating apparatus with non- oxidizing furnace.

HIGH-STRENGTH HOT-ROLLING STEEL AND PROCEDURE FOR THE PRODUCTION OF VOLUMES

PROCEDURE FOR THE PRODUCTION OF VOLUMES AND ROLLING TRAIN

DISTILLATION COLUMN WITH PACKING MATERIAL AND PROCEDURE FOR DISTILLATIVES THE SEPARATION FROM MATERIAL MIXTURES WITH THIS PACKING MATERIAL

PROCEDURE FOR MANUFACTURING COLD-ROLLED ONE METALLIZED STEEL PRODUCTS WITH LOW ONE APPARENT YIELDING POINT TENSILE STRENGTH, AND THEREBY RECEIVED PRODUCTS

Steel sheet, in particular for the production of profiles, pipes and composite structures

PROCEDURE FOR THE PRODUCTION OF STAINLESS STEEL STRIPS AND INTEGRATED ROLLING TRAIN

Dual phase steel strip suitable for galvanizing

HIGH-STRENGTH THIN STEEL SHEET DRAWABLE AND EXCELLENT IN SHAPE FIXATION PROPERTY AND METHOD OF PRODUCING THE SAME

The present invention provides a high-strength thin steel sheet drawable and excellent in a shape fixation property and a method of producing the same. The present invention is a high-strength thin steel sheet drawable and excellent in a shape fixation property, characterized in that: on a plane at the center of the thickness of a steel sheet, the average ratio of the X-ray strength in the orientation component group of {100}<011> to {223}<110> to random X-ray diffraction strength is 2 or more and the average ratio of the X-ray strength in three orientation components of {554}<225>, {111}<112> and {111}<110> to random X-ray diffraction strength is 4 or less; the arithmetic average of the roughness Ra of at least one of the surfaces is 1 to 3.5 (m; the surfaces of the steel sheet are covered with a composition having a lubricating effect; and the friction coefficient of the steel sheet surfaces at 0 to 200~C is 0.05 to 0.2. Further, the present invention is a method of producing said steel ...

ALUMINUM PLATED STEEL SHEET FOR RAPID HEATING HOT-STAMPING, PRODUCTION METHOD OF THE SAME AND RAPID HEATING HOT-STAMPING METHOD BY USING THIS STEEL SHEET

The present invention solves the problem of melting of Al in heating before hot-stamping, which had been a problem in the past in applying hot-stamping to Al-plated steel sheet, and provides Al-plated steel sheet for hot-stamping and a method of hot-stamping using that Al-plated steel sheet to solve the problem of delayed fracture due to residual hydrogen, and, furthermore, a method of a rapid heating hot-stamping using that Al-plated steel sheet. The Al-plated steel sheet of the present invention is produced by annealing the Al-plated steel sheet as coiled in a box-anneal furnace for the time and at the temperature indicated in Fig. 5, and alloying of a plated Al and a steel sheet. Further, a method of rapid heating hot-stamping in the present invention is characterized by cutting out a stamping blank of an Al-plated steel sheet, and heating that blank in heating before hot-stamping by an average temperature with a rising rate of 40°C/sec or more and a time of exposure to an environment ...

METHOD AND APPARATUS FOR MANUFACTURING METAL STRIPS

The invention relates to a method for producing metal strips (1) in a device (2), wherein a metal strip, in particular a thin slab, is brought to a desired temperature in an oven (3, 3a, 3b) and/or maintained at the desired temperature, and undergoes a rolling process in a rolling mill (4) in the direction of conveyance (R) of the metal strip (1) behind the oven (3, 3a, 3b). According to the invention, in order to prevent scale deposits in the rear region of the oven, the metal strip (1) undergoes at least one descaling operation during the journey thereof in an area (5) of the oven (3, 3a, 3b). The invention also relates to a device for producing metal strips.

PROCESS FOR PRODUCING HIGH TENSILE HOT-DIP ZINC-COATED STEEL SHEET OF EXCELLENT DUCTILITY AND ANTIFATIGUE PROPERTIES

A hot rolled plate of a composition comprising 0.05 to 0.20 mass% of C, 0.3 to 1.8 mass% of Si, 1.0 to 3.0 mass% of Mn and the remainder consisting of Fe and inevitable impurities, having a composite texture consisting of ferrite main phase and second phase wherein the second phase comprises 80 vol.% or more of bainite and the remainder consisting of any one or two or more of martensite, retained austenite and pearlite and wherein the ratio of plate-thickness- direction average length to average length of the second phase is 0.7 or more, as a starting material, is subjected to cold rolling, given heat treatment, hot dip zinc coating and cooling operations. As a result, there can be obtained a high tensile hot-dip zinc-coated steel sheet exhibiting a ductility that is satisfactory for use as a material of automobile parts and also excellent antifatigue properties.

HIGH STRENGTH GALVANIZED STEEL PLATE EXCELLENT IN ADHESION OF PLATED METAL AND FORMABILITY IN PRESS WORKING AND HIGH STRENGTH ALLOY GALVANIZED STEEL PLATE AND METHOD FOR PRODUCTION THEREOF

HIGH TENSILE STRENGTH HOT-DIPPED STEEL SHEET AND METHOD OR PRODUCING THE SAME

A method for producing a high tensile strength hot dip plated steel sheet, which comprises providing a steel sheet having a Si content controlled within a specific range and comprising Nb and one or more of Cu, Ni and Mo, subjecting a rolled sheet to a recrystallization annealing to thereby form an inner oxide layer close under the surface of the steel plate, washing the surface with an acid to remove the oxides having been formed also on the surface, heating the resultant steel sheet prior to plating, and then subjecting the sheet to a hot dip plating. The inner oxide layer formed during annealing acts as a barrier against diffusion of Si, Mn and the like during the heat treatment prior to plating, which results in marked reduction of the formation of oxides of Si, Mn and the like. Accordingly, the method can be used for producing a high tensile strength hot dip plated steel sheet which exhibits markedly excellent plating characteristics.

COLD ROLLED HIGH STRENGTH LOW ALLOY STEEL

The invention relates to a high strength low alloy steel. According to the invention the high strength low alloy steel strip, sheet or blank, coated with zinc or a zinc alloy, has the following composition in weight%: C: 0.03 - 0.07, Mn: 0.70 - 1.60, Si: = 0.01 - 0.2, Al: 0.005 - 0.1, Cr: = 0.1, Cu: = 0.2, N: = 0.008, P: = 0.03, S: = 0.025, O: = 0.01, Ti: 0.02 - 0.07, V: 0.04 - 0.15, Mo: = 0.03, Nb: = 0.03, Ca: = 0.05, the remainder being iron and unavoidable impurities, wherein the steel strip, sheet or blank has a yield strength Rp0,2 of at least 420 MPa.

HIGH STRENGTH HOT DIP GALVANISED COMPLEX PHASE STEEL STRIP

The invention relates to a high strength hot dip galvanised complex phase steel strip consisting, in mass percent, of the following elements: 0.13-0.19 %C, 1.70- 2.50 %Mn, max 0.15 % Si, 0.40 - 1.00 % Al, 0.05 - 0.25 % Cr, 0.01 - 0.05 % Nb, max 0.10 % P, max 0.004 % Ca, max 0.05 % S, max 0.007 % N, and optionally at least one of the following elements: max 0.50 % Ti, max 0.40 % V, max 0.50 % Mo, max 0.50 % Ni, max 0.50 % Cu, max 0.005 % B, the balance being Fe and inevitable impurities, wherein 0.40 % < Al + Si < 1.05 % and Mn + Cr > 1.90 %, and having a complex phase microstructure, in volume percent, comprising 8-12 % retained austenite, 20 - 50 % bainite, less than 10 % martensite, the remainder being ferrite, as well as to a method of producing the same.

HIGH STRENGTH MULTIPHASE STEEL, PRODUCTION METHOD AND USE

The invention deals with a cold rolled and hot dip steel sheet, with a tensile strength of at least 980 MPa, with yield strength above or equal to 500 MPa, with total elongation above or equal to 8%, the composition consisting by weight percent: 0.05 < C < 0.15%, 2 < Mn= 3%, Al < 0.1 %, 0.3 < Si < 1.5%, 0.01 % < Nb < 0.05%, N < 0.02%, 0.1 < Cr + Mo < 1 %, 0.0001 < B < 0.0025, Ti < 0.5%, V < 0.01 %, S < 0.01 %, P < 0.05% the remainder of the composition being iron and unavoidable impurities resulting from the smelting and the microstructure contains, in surface fraction: between 50 and 95 % of martensite and between 5 and 50 % of the sum of ferrite and bainite, wherein the ferrite grain size is below 10 µ?t?, and wherein the aspect ratio of the ferrite grain size is between 1 and 3. The steel according to the invention is oxidized and subsequently reduced during heating, soaking and cooling steps of the annealing.

COLD ROLLED STEEL SHEET, METHOD OF MANUFACTURING AND VEHICLE

The invention deals with a cold rolled and hot dip coated steel sheet presenting a tensile strength above 1000 - 50xAI MPa, a uniform elongation above 15% and a low density. The steel comprises, by weight percent: 0.1 = C = 0.5%, 3.5 = Mn = 10.0%, 0 = Al = 9.0%, Si = 5.0%, Ti = 0.2%, V = 0.2%, Nb = 0.2%, S = 0.004 %, P = 0.025 %, 0.5 = Si+AI = 9.0%, B = 0.0035, Cr = 1%, The balance being Fe and impurities and the microstructure containing 25% to 90% of ferrite, 10% to 50 % of austenite, kappa precipitates lower than 5% and martensite lower than 25%. The steel according to the invention presents the ability to be coated using total oxidation.

METHOD FOR PRODUCING A FLAT STEEL PRODUCT PROVIDED WITH A METAL PROTECTIVE LAYER BY WAY OF HOT DIP COATING

Optimal wetting and adhesion of the hot-dip coating by way of pre-oxidation in a DFF pre-heating furnace and humidification of the annealing atmosphere in a holding zone is achieved in a hot dip galvanized flat steel product. For this purpose firstly the 550 - 850 °C flat steel product is exposed in a pre-oxidation section of the DFF furnace within 1 - 15 s to an oxidising atmosphere, introduced by blowing a flow of gas containing oxygen into the flame of a burner, to form a covering FeO layer on its surface, whereas outside of the pre-oxidation section an atmosphere prevails in the DFF furnace which is reducing or neutral with respect to the surface of the steel. The flat steel product heated to a holding temperature of 600 - 1, 100 °C in this way is then recrystallisation annealed under a FeO-reducing atmosphere, the dew point of which is held at -40 °C to +25 °C by the addition of moisture, cooled to a bath entry temperature of 420 - 700 °C under an atmosphere having <= 100% N2 and a ...

HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND HIGH-STRENGTH ALLOYED HOT-DIP GALVANIZED STEEL SHEET HAVING EXCELLENT FORMABILITY AND SMALL MATERIAL ANISOTROPY WITH ULTIMATE TENSILE STRENGTH OF 980 MPA OR MORE AND MANUFACTURING METHOD THEREFOR

Provided is a high-strength hot-dip galvanized steel sheet having small material anisotropy and excellent formability with an ultimate tensile strength of 980 MPa or more. The hot-dip galvanized steel sheet includes a hot-dip galvanized layer formed on a surface of a base steel plate. The base steel plate contains, by mass%, C: 0.1 to less than 0.40%, Si: 0.5 to 3.0%, Mn: 1.5 to 3.0%, O: limited to 0.006% or less, P: limited to 0.04% or less, S: limited to 0.01% or less, Al: limited to 2.0% or less, N: limited to 0.01% or less, and a balance including Fe and inevitable impurities. A microstructure of the base steel sheet contains ferrite of 40% or more, residual austenite of 8 to less than 60%, by volume fraction, and a balance being bainite or martensite. In a sheet thickness range of 5/8 to 3/8 from the surface of the base steel sheet, a pole density of specific crystal orientation is within a predetermined range. The hot-dip galvanized layer contains Fe: less than 7 mass% and a balance ...

HIGH-YIELD RATIO AND HIGH-STRENGTH THIN STEEL SHEET SUPERIOR IN WELDABILITY AND DUCTILITY, HIGH-YIELD RATIO HIGH-STRENGTH HOT-DIP GALVANIZED THIN STEEL SHEET, HIGH-YIELD RATIO HIGH-STRENGTH HOT-DIP GALVANNEALED THIN STEEL SHEET, AND METHODS OF PRODUCTION OF SAME

High yield ratio high-strength thin steel sheet superior in weldability and ductility characterized by; being comprised of steel containing, by mass%, C: over 0.030 to less than 0.10%, Si: 0.30 to 0.80%, Mn: 1.7 to 3.2%, P: 0.001 to 0.02%, S: 0.0001 to 0.006%, Al: 0.060% or less, N: 0.0001 to 0.0070%, containing further Ti: 0.01 to 0.055%, Nb: 0.012 to 0.055%, Mo: 0.07 to 0.55%, B: 0.0005 to 0.0040%, and simultaneously statisfying 1.1<=14xTi(%)+20xNb(%)+3xMo($)+300xB(%)<=3.7, the balance comprised of iron and unavoidable impurities, and having a yield ratio of 0.64 to less than 0.92, a TSxEl of 3320 or more, an YRxTSxEl1/2 of 2320 or more, and a maximum tensile strength (TS) of 780 MPa or more.

COLD-ROLLED STEEL SHEET AND METHOD FOR PRODUCING SAME

The cold-rolled steel sheet has a mean pole density of {100} <011>~ {223} <110> orientations that is between 1.0 and 5.0; a pole density of {332} <113> crystal orientation that is between 1.0 and 4.0; an rC, which is the Lankford coefficient perpendicular to the rolling direction, that is between 0.70 and 1.50; an r30, which is the Lankford coefficient at a 30º angle to the rolling direction, that is between 0.70 and 1.50; and a metal composition, by vol%, of 30 to 99% ferrite + bainite and 1 to 70% of martensite.

FERRITE-BASED STAINLESS STEEL PLATE HAVING EXCELLENT RESISTANCE AGAINST SCALE PEELING, AND METHOD FOR MANUFACTURING SAME

This ferrite-based stainless steel plate contains, by mass, 0.02% or less of C, 0.02% or less of N, 0.05 to 0.80% of Si, 0.05 to 1.00% of Mn, 0.04% or less of P, 0.01% or less of S, 12 to 20% of Cr, 0.80 to 1.50% of Cu, 1.0% or less of Ni, 0.01 to 2.00% of Mo, 0.30 to 1.00% of Nb, 0.01% to less than 0.25% of Ti, 0.003 to 0.46% of Al, 0.01 to less than 0.15% of V, and 0.0002 to 0.0050% of B, with equation (1) or (2) being satisfied, the remainder being made up by Fe and unavoidable impurities, and the average Cu concentration between the surface and a depth of 200 nm being no greater than 3.00%. If Mn < 0.65%: 1.44 × Si - Mn - 0.05 = 0...(1) If Mn = 0.65%: 1.10 × Si + Mn - 1.19 = 0...(2) ...

HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND HIGH-STRENGTH ALLOYED HOT-DIP GALVANIZED STEEL SHEET EXCELLENT IN MECHANICAL CUTTING PROPERTY, AND MANUFACTURING METHOD THEREOF

Provided is a high-strength hot-dip galvanized steel sheet and the like, said steel sheet providing high ductility while ensuring high strength with a maximum tensile strength of at least 900 MPa, and having excellent mechanical cutting characteristics. The high-strength hot-dip galvanized steel sheet has a thickness of 0.6 to 5.0 mm, and has a plating layer on a surface of the steel sheet for which component compositions have been set within appropriate ranges. The structure of the steel sheet includes a ferrite phase with a volume fraction of 40 to 90%, and a retained austenite phase with a volume fraction of at least 3%. The retained austenite phase has a solute carbon content of 0.70 to 1.00%, an average particle size of 2.0 µm or less, and an average distance between particles of 0.1 to 5.0 µm. The thickness of a decarburized layer in a surface section of the steel sheet is 0.01 to 10.0 µm, and the average particle size and average density of oxides contained in the surface section ...

HIGH-FORMABILITY AND SUPER-STRENGTH HOT GALVANIZING STEEL PLATE AND MANUFACTURING METHOD THEREOF

A high-formability and super-strength hot galvanizing steel plate. The weight percentage of its chemical components: C: 0.15-0.25wt%, Si: 1.00-2.00wt%, Mn: 1.50-3.00wt%, P=0.015wt%, S=0.012wt%, Al: 0.03-0.06wt%, N=0.008wt%, and the rest are Fe and inevitable impurities. The microstructure of the steel plate at room temperature is the ferrite of 10-30%, the martensite of 60-80% and the retained austenite of 5-15%; and the yield strength of 600-900 MPa, the tensile strength of 980-1200 MPa, and the elongation of 15-22%. Through proper involved components, a super-strength cool-rolled hot galvanizing steel plate is produced by continuous annealing, without adding any expensive alloying element. By only properly improving the content of Si and Mn and combining proper annealing and furnace atmosphere control processes, the strength of the steel plate can improve substantially, and the plasticity is also desirable. Meanwhile, the galvanizing quality of the steel plate is good, and the use requirement ...

HIGH-FORMABILITY AND SUPER-STRENGTH COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREOF

A high-formability and super-strength cold-rolled steel sheet and a manufacturing method thereof. The weight percentage of its components is: C 0.15~0.25%, Si 1.00~2.00%, Mn 1.50~3.00%, P=0.015%, S=0.012%, Al 0.03~0.06%, N=0.008%, and the rest are Fe and inevitable impurities. The manufacturing method comprises the following steps: 1) smelting and casting; 2) heating to 1170~1230°C and performing thermal insulation; 3) performing hot rolling, the finish rolling temperature being 880±30°C, and coiling at 550~650°C; and 4) performing acid washing, cold rolling, and annealing, the cold rolling reduction being 40~60%, annealing at 860~920°C, and performing slow cooling to 690~750°C with the cooling rate of 3~10°C/s; performing rapid cooling at 240~320°C, with the cooling rate =50°C/s, then heating to 360~460°C, and performing thermal insulation for 100~500s to cool to the room temperature at last. Finally, a high-formability, low-rebound property and super-strength cold-rolled steel sheet with ...

METHOD FOR THE PRODUCTION OF PRESS-HARDENED, COATED STEEL PARTS AND PRE-COATED STEEL SHEETS THAT CAN BE USED FOR THE PRODUCTION OF SAID PARTS

L'invention concerne une tôle laminée a froid et recuite pré-revêtue pour la fabrication de pièces durcies sous presse, composée d'un substrat d'acier pour traitement thermique contenant une teneur en carbone C0 comprise entre 0,07% et 0,5%, ladite teneur étant exprimée en poids, et d'un pré-revêtement métallique au moins sur les deux faces principales dudit substrat d'acier, caractérisée en ce que ledit substrat comporte une zone décarburée a la surface de chacune de ses deux faces principales, la profondeur p50% de ladite zone décarburée étant comprise entre 6 et 30 micromètres, p50% étant la profondeur a laquelle la teneur en carbone est égale a 50% de ladite teneur C0, et en ce que ladite tôle ne contient pas de couche d'oxyde de fer entre ledit substrat et ledit pré-revêtement métallique.

Stahlblech, insbesondere für die Herstellung von Verbundkonstruktionen

PROCESS FOR MANUFACTURING STEEL SHEETS FOR PRESS HARDENING, AND PARTS OBTAINED BY MEANS OF THIS PROCESS

STEEL SHEET PROVIDED WITH A COATING OFFERING SACRIFICIAL CATHODIC PROTECTION, METHOD FOR THE PRODUCTION OF A PART USING SUCH A SHEET, AND RESULTING PART

METHOD OF MAKING SHEET STAINLESS STEEL WITH MODIFIED BY VISUAL CHARACTERISTICS

СПОСОБ ПРОИЗВОДСТВА ХОЛОДНОКАТАНОГО И ОТОЖЖЕННОГО ЛИСТА ИЗ ДВУХФАЗНОЙ СТАЛИ, ПОЛУЧЕННЫЙ ТАКИМ СПОСОБОМ ЛИСТ, СПОСОБ ПРОИЗВОДСТВА ХОЛОДНОКАТАНОГО, ОТОЖЖЕННОГО И ОЦИНКОВАННОГО ЛИСТА ИЗ ДВУХФАЗНОЙ СТАЛИ (ВАРИАНТЫ) И ИСПОЛЬЗОВАНИЕ УКАЗАННОГО СТАЛЬНОГО ЛИСТА

Изобретение относится к холоднокатаному и отожженному листу двухфазной стали, имеющему прочность от 980 до 1100 МПа и, который характеризуется удлинением при разрыве выше 9 %, композиция которой включает, масс. %: 0,055≤С≤0,095, 2≤Mn≤2,6, 0,005≤Si≤0,35, S≤0,005, Р≤0,050, 0,1≤А1≤0,3, 0,05≤Мо≤0,25, 0,2≤Cr≤0,5, при условии, что Cr+2Mo≤0,6, Ni ≤0,1, 0,010≤Nb≤0,040, 0,010≤Ti≤0,050, 0,0005≤В≤0,002 и 0,002≤N≤0,007, остальное - железо и необязательные примеси. Также заявлен способ производства указанного листа, способ производства холоднокатаного, отожженного и оцинкованного листа из двухфазной стали, и применение указанного листа.

СТАЛЬНАЯ ДЕТАЛЬ, ОХЛАЖДЕННАЯ ВЫДЕРЖКОЙ В ОБОРУДОВАНИИ, СВАРНОЕ ИЗДЕЛИЕ С ИСПОЛЬЗОВАНИЕМ ЭТОЙ ДЕТАЛИ, ЕЕ ИЗГОТОВЛЕНИЕ С ПРЕДВАРИТЕЛЬНЫМ ПОКРЫТИЕМ И БЕЗ НЕГО И ПРИМЕНЕНИЕ УКАЗАННОЙ СТАЛЬНОЙ ДЕТАЛИ

Изобретение относится к области черной металлургии, а именно к способу изготовления стальной детали с покрытием, без покрытия, сварного изделия с использованием ее, применение этой детали и детали, полученной охлаждением выдержкой в оборудовании из стали с содержанием, в мас. %: 0,040 ≤ С ≤ 0,10, 0,80 ≤ Mn ≤ 2,0, Si ≤ 0,30, S ≤ 0,005, Р ≤ 0,030, 0,01 ≤ Al ≤ 0,07, 0,015 ≤ Nb ≤ 0,100, 0,030 ≤ Те ≤ 0,080, N ≤ 0,009, Cu ≤ 0,100, Ni ≤ 0,100, Cr ≤ 0,100, Мо ≤ 0,100, Са ≤ 0,006, остальные - железо и неизбежные примеси, образованные в результате производства, и микроструктура этой стали составлена по крайней мере с 75% равноосного феррита, 20% ≥ мартенсита ≥ 5% и бейнита <10%. Изобретение обеспечивает повышение прочности стальной детали толщиной 0,5- после горячей деформационной обработки до величины более 500 МПа с относительным удлинением до величины более 15%, гомогенности структуры и стабильности механических свойств всех ее участков.

METHOD FOR THE PRODUCTION OF PRESS-HARDENED, COATED STEEL PARTS AND PRE-COATED STEEL SHEETS THAT CAN BE USED FOR THE PRODUCTION OF SAID PARTS

A METHOD OF ANNEALING STEEL SHEETS

METHOD FOR PRODUCING A ULTRA HIGH STRENGTH COATED OR NOT COATED STEEL SHEET AND OBTAINED SHEET

HOT-ROLLED STEEL SHEET AND ASSOCIATED MANUFACTURING METHOD

MARTENSITIC STEEL WITH DELAYED FRACTURE RESISTANCE AND MANUFACTURING METHOD

HIGH STRENGTH MULTIPHASE STEEL, PRODUCTION METHOD AND USE

METHOD FOR PRODUCING A ULTRA HIGH STRENGTH GALVANNEALED STEEL SHEET AND OBTAINED GALVANNEALED STEEL SHEET

STEEL SHEET PROVIDED WITH A COATING OFFERING SACRIFICIAL CATHODIC PROTECTION, METHOD FOR THE PRODUCTION OF A PART USING SUCH A SHEET, AND RESULTING PART

Alloyed hot-dip galvanized steel sheet and production method thereof

Disclosed is an alloyed hot-dip galvanized steel sheet containing 2.0 to 3.5 percent by mass of Mn. The steel sheet includes a base steel sheet and a galvanized zinc-coat layer thereon, in which MnO particles are present in an average number of 10 or less per micrometer on a straight line lying in an interface between the galvanized zinc-coat layer (2) and the steel sheet (1), an Fe-Al-O alloy layer is present at the interface between the MnO particles and the steel sheet (1), and the length of the Fe-Al-O alloy layer is less than 10% of the overall length of the interface. The alloyed hot-dip galvanized steel sheet, even though having a high Mn content, is resistant to uneven alloying and excels in surface appearance, because the amounts of the MnO particles and the Fe-Al-O alloy layer that cause uneven alloying are controlled.

Method and manufacturing apparatus for producing ferritic stainless steel cold-rolled steel strip, and cold rolling mill of ferritic stainless steel strip

For manufacturing ultra-high strength steel plate coated or non-coated method and the obtained plate

MANUFACTORING PROCESS Of a FERRITIC STAINLESS STRIP STEEL HAS HIGH ALUMINIUM CONTENT USABLE IN PARTICULAR FOR a CATALYST SUPPORT Of EXHAUST OF MOTOR VEHICLE

Composite object out of steel and its method of preparation

METHOD FOR REALIZATION Of a PART HAS VERY HIGH MECHANICAL CHARACTERISTICS, SETTING FORMS some BY STAMPING, STARTING FROM a STEEL SHEET BAND LAMINEE ETNOTAMMENT LAMINEE HOT AND COVERED

A METHOD FOR PREPARING BANDS OR STEEL SHEETS STAINLESS, AUSTENITIC, PRESENTING a STRENGTH RAISED FATIGUE, AND SHEETS PREPAREES BY THIS PROCESS

SHEET Of STEEL LAMINEE HOT AND COLD COVERED AND COMPRISING a VERY HIGH STRENGTH AFTER HEAT TREATMENT

Tôle d'acier laminée à chaud et à froid, revêtue et comportant une très haute résistance après traitement thermique, l'acier ayant la composition pondérale suivante : 0, 15% < carbone < 0, 5% 0, 5% < manganèse < 3% 0, 1% < silicium < 0, 5% 0, 01% < chrome < 1%, titane < 0, 2%, aluminium < 0, 1%, phosphore < 0, 1%, soufre < 0, 05%, 0, 0005% < bore < 0, 08%, et comportant un revêtement à base d'aluminium.

GOLD COLOR STEEL PLATE AND MANUFACTURING METHOD THEREOF

A gold color plate capable of exhibiting color without peeling of a modified layer and a manufacturing method thereof capable of forming a color-modified layer through a normal annealing process without expensive special equipment are disclosed. According to one embodiment of the present invention, the manufacturing method can form a titanium-nitrogen (Ti-N) modified layer on the surface of a steel plate by annealing and heating the steel plate containing 0.3 to 1.5% by weight of titanium (Ti) at 900 °C to 1,200 °C for 30 to 300 seconds in the nitrogen (N2) atmosphere. COPYRIGHT KIPO 2018 (AA) Use Ti ...

판상 강 제품 및 판상 강 제품의 제조방법

... 본 발명은 열간 프레스 성형에 의해 부품으로 성형되고, Zn 또는 Zn 합금에 의해 형성된 금속 부식-방지 코팅이 위에 도포된 강으로 제조된 베이스를 가지는 판상 강 제품에 대한 것이다. 이는 본 발명에 따라 달성되는 데, 적어도 하나의 비금속 화합물(산화물, 질화물, 황화물, 황산염, 탄화물, 탄산염, 불화물, 수화물(hydrate), 수산화물, 또는 인산염-화합물)을 함유하는 판상 강 제품의 자유 표면 위에 별도의 마무리 코팅이 도포됨으로써 달성된다. 또한, 본 발명은 이러한 종류의 판상 강 제품을 제조할 수 있는 방법에 대한 것이다.

고강도 강판 및 그 제조 방법

... 고가의 합금 원소를 적극적으로 함유하지 않은 성분계에 있어서, 우수한 연신율, 신장 플랜지성, 굽힘성을 갖는 가공성이 우수한 인장 강도 (TS) 900 ㎫ 이상의 고강도 강판을 얻는다. 질량％ 로, C : 0.15 ∼ 0.40 ％, Si : 1.0 ∼ 2.0 ％, Mn : 1.5 ∼ 2.5 ％, P : 0.020 ％ 이하, S : 0.0040 ％ 이하, Al : 0.01 ∼ 0.1 ％, N : 0.01 ％ 이하 및 Ca : 0.0020 ％ 이하를 함유하고, 잔부가 Fe 및 불가피 불순물로 이루어지는 성분 조성을 갖고, 조직 전체에 대한 면적 비율로, 페라이트상과 베이나이트상의 합계가 40 ∼ 70 ％, 마텐자이트상이 20 ∼ 50 ％, 잔류 오스테나이트상이 10 ∼ 30 ％ 인 조직을 갖는 것을 특징으로 하는 고강도 강판으로 한다.

개선된 연성을 갖는 툴리스 열간 성형 또는 급냉용 강

... 본 발명은 강 부품에 관한 것으로서, 강의 조성은 중량 % 로, 0.040 % ≤ C ≤0.100 %, 0.80 % ≤ Mn ≤2.00 %, Si ≤ 0.30 %, S ≤ 0.005 %, P ≤ 0.030 %, 0.010 % ≤ Al ≤0.070 %, 0.015 % ≤ Nb ≤0.100 %, 0.030 % ≤ Ti ≤0.080 %, N ≤ 0.009 %, Cu ≤ 0.100 %, Ni ≤ 0.100 %, Cr ≤ 0.100 %, Mo ≤ 0.100 %, Ca ≤ 0.006 % 를 함유하고, 잔부는 철 및 제련으로 인한 불가피한 불순물로 이루어지며, 상기 강의 미세 조직은 적어도 75 % 의 등축 페라이트, 5 % 이상 ~ 20 % 이하의 마르텐사이트 및 10 % 이하의 베이나이트로 이루어진다.

높은 항복 강도를 갖는 냉간-압연 판상 강 제품을 제조하기 위한 방법 및 판상 냉간-압연 강 제품

... 발명은 항복 비(Re/Rm)이 적어도 0.7인 냉간-압연 강 스트립을 제조하기 위한 방법을 제공하며, 냉간-압연 강 제품은, 철과 불가피한 불순물과 더불어, 중량%로 C: 0.05% 내지 0.20%, Si: 0.25% 내지 1.00%, Mn: 1.0% 내지 3.0%, Al: 0.02% 내지 1.5%, Cr: 0.1% 내지 1.5%, N: 0.02% 미만, P: 0.03% 미만, S: 0.05% 미만 및 선택적으로 Ti: 0.15% 이하, Mo: 2% 미만, Nb: 0.1% 미만, V: 0.12% 미만 및 B: 0.0005% 내지 0.003%의 조건 하에서 "Ti, Mo, Nb, V, B"의 그룹으로부터의 하나 이상의 원소를 포함하는 강으로 이루어진다. 본 발명에 따르면, 제공된 냉간-압연 판상 강 제품은 추가로 열처리되며, 열처리 중에 150oC 내지 400oC까지의 소둔 온도에서 4.5시간 내지 24시간의 소둔 시간 동안 소둔된다. 경이롭게도, 비교적 낮은 온도에서 실시된 그와 같은 장시간 소둔의 결과로서, 항복 강도(Re)의 현저한 증가와 구멍 확장성의 향상이 일어난다. 본 발명은, 위에 언급된 강으로 이루어지고, 적어도 2개의 상을 포함하되, 체적%로 적어도 10 체적%의 템퍼드 마르텐사이트, 10 체적% 미만의 베이나이트, 10 체적% 미만의 잔류 오스테나이트 및 잔부로서 페라이트를 포함하는 조직을 갖는 냉간-압연 판상 강 제품을 또한 제공하며, 강은 적어도 0.7의 항복 비(Re/Rm), 750MPa을 초과하는 인장 강도(Rm) 및 적어도 18%의 구멍 확장성(LA)을 갖는다.

ALUMINUM-PLATED STEEL SHEET FOR HOT PRESSING WITH RAPID HEATING, PROCESS FOR PRODUCING SAME, AND METHOD OF HOT-PRESSING SAME WITH RAPID HEATING

A METHOD FOR COATING A FLAT PRODUCT OF HOT ROLLED STEEL OR COLD ROLLED, CONTNDO 6 - 30% BY WEIGHT OF MN, WITH A METALLIC PROTECTIVE LAYER

steel plate laminated to cold high strength, steel plate electroplated hot dip high strength steel plate and electroplated high strength

peça de aço revestida endurecida por prensagem, processo para fabricar uma peça de aço revestida endurecida por prensagem e uso de uma peça endurecida por prensagem

chapa de aço galvanizada por imersão a quente de alta resistência com excelente resistência ao destacamento por impacto e resistência à corrosão em seção trabalhada

Steel sheet having hot-dip galvanized layer and exhibiting superior plating wettability and plating adhesion, and production method therefor

Provided are a steel sheet that has a hot-dip galvanized layer and that exhibits superior plating wettability and plating adhesion, and a production method therefor. A steel sheet containing readily oxidizable elements including Si and Mn is used as a base material. The hot-dip galvanized steel sheet has a hot-dip galvanized layer (A) on the surface of the steel sheet and is characterized by having a (B) layer that is directly under the surface of and inside of the steel sheet. The (B) layer has a thickness of 0.001 mum to 0.5 mum. By mass, the (B) layer contains 50 mass% or more of unoxidized Fe, less than 50 mass% total of one or more oxides of Fe, Si, Mn, P, S, and/or Al, and contains unoxidized C, Si, Mn, P, S, and/or Al in the following quantities: less than 0.05 mass% of C; less than 0.1 mass% of Si; less than 0.5 mass% of Mn; less than 0.001 mass% of P; less than 0.001 mass% of S; and less than 0.005 mass% of Al.

A high strength hot-dip galvanized steel sheet composed of composite microstructure having excellent formability and hole expandability, and a method for production the same

The present invention provides a high strength hot-dip galvanized steel sheet composed of composite microstructure having excellent formability and hole expandability, and a method for production the same. This steel sheet contains, in mass, c:0.01-0.3%, Si:0.005-0.6%, Mn:0.1-3.3%, P:0.001-0.06%, s:0.001-0.01%, Al:0.01-1.8%, N:0.0005-0.01%, and the balance being Fe and unavoidable impurities, and has a microstructure composed of ferrite and tempered martensite having the area ratio of more than 5% and less than 60%. Further, this high strength hot-dipg alvanized steel sheet is produced by the steps comprising; hot rolling the slab containing the above mentioned compositions, cold rolling the hot rolles steel sheet, heating the cold rolled steel sheet at a temperature between AC1 and AC3+100 DEG C, cooling the heated steel sheet to 450-600 DEG C at a cooling rate of more than 1 DEG c/sec, dipping the cooled steel sheet in Zn hot bath for hot-dip galvanizing, cooling the galvanized steel ...

METHOD AND DEVICE FOR HOT SHEET METAL FORMING

In a method for hot sheet metal forming, a sheet metal is heated to a temperature less than or equal to the Curie temperature in a first step by induction heating by means of a first induction heating device, and in a second step the sheet metal is heated to temperatures greater than 800 °C by means of conventional heating in a furnace or by means of induction heating in a second induction heating device different from the first induction heating device.

HIGH-STRENGTH HOT-DIP GALVANIZED STEEL PLATE HAVING EXCELLENT IMPACT RESISTANCE AND METHOD FOR PRODUCING SAME, AND HIGH-STRENGTH ALLOYED HOT-DIP GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING SAME

This base steel sheet has a hot-dip galvanized layer formed on the surface, and the volume fraction of a retained austenite phase of the steel sheet structure in a range of 1/8 of the sheet thickness to 3/8 of the sheet thickness, centered around 1/4 of the sheet thickness, from the surface, is not more than 5%, and the total volume fraction of a bainite phase, a bainitic ferrite phase, a fresh martensite phase, and a tempered martensite phase is not less than 40%. The average effective grain size is not more than 5.0 μm, and the maximum effective grain size is not more than 20 μm. A decarburized layer with a thickness of 0.01 to 10.0 μm is formed on a surface section, the density of oxides, which are dispersed in the decarburized layer is 1.0 × 1012 to 1.0 × 1016 oxides/m2, and the average particle size of the oxides is not more than 500 nm.

Process for manufacturing a cold rolled trip steel product

The present invention is related to a process comprising a cold rolling step, for the production of uncoated, electro-galvanised or hot dip galvanised TRIP steel products, hot rolling a slab of a specific composition, wherein the finishing rolling temperature is higher than the Ar3 temperature, to form a hot-rolled substrate, cooling said substrate to a coiling temperature (CT) between 500° C. and 680° C., coiling said substrate at said coiling temperature, pickling said substrate to remove the oxides, cold rolling said substrate to obtain a reduction of thickness, with a minimum reduction of 40%.

Strip, Sheet or Blank Suitable for Hot Forming and Process for the Production Thereof

Disclosed is a strip, sheet or blank suitable for hot forming at a temperature of 700° C. or above, including a substrate of hot formable steel, optionally coated with an active corrosion protective coating. The optionally coated steel substrate is provided with a ceramic based coating having a thickness of at most 25 micron. Also disclosed is a process to produce such strip, sheet or blank.

Method of producing cold-rolled steel sheet as well as cold-rolled steel sheet and members for automobile

In a method of producing a cold-rolled steel sheet being excellent in not only the phosphate treatability but also the corrosion resistance after coating under severe corrosion environment such as hot salt water immersion test or composite cycle corrosion test, a continuously annealed steel sheet after cold rolling preferably including 0.5-3.0 mass % of Si is pickled to remove a Si-containing oxide layer on a surface layer of the steel sheet and further repickled so that a surface covering ratio of an iron-based oxide on the surface of the steel sheet is not more than 40% and preferably a maximum thickness of the iron-based oxide is not more than 150 nm, as well as a cold-rolled steel sheet produced by this method and a member for automobile using the cold-rolled steel sheet.

Hot-dip galvanized steel sheet and manufacturing method thereof

A hot-dip galvanized steel sheet includes a steel sheet and a hot-dip galvanized layer arranged on the steel sheet, in which the Si content and the Al content by mass % of components of the steel sheet satisfy a relationship 0.5<Si+Al<1.0, and a metallographic structure of the steel sheet satisfies a relationship of {(n 2 ) 2/3 ×d 2 }/{(n 1 ) 2/3 ×d 1 }×ln(H 2 /H 1 )<0.3 when the n 1 is the number of a MnS of a surface portion of the steel sheet, the d 1 μm is an average equivalent circle diameter of the MnS in the surface portion of the steel sheet, the H 1 GPa is a hardness of a martensite of the surface portion of the steel sheet, the n 2 is the number of the MnS of a center portion of the steel sheet, the d 2 μm is an average equivalent circle diameter of the MnS in the center portion of the steel sheet, and the H 2 GPa is the hardness of the martensite of the center portion of the steel sheet.

Flat Steel Product and Method for Producing a Flat Steel Product

A flat steel product, intended to be formed into a component by hot press forming and having a base made of steel, onto which a metal anti-corrosion coating of a Zn or a Zn alloy is applied. A separate finishing coat is applied to at least one of the free surfaces of the flat steel product. The finishing coat includes at least one base metal compound (oxide, nitride, sulphide, sulphate, carbide, carbonate, fluoride, hydrate, hydroxide, or phosphate). Also, a method enabling the production of a flat steel product of this kind.

Mn-CONTAINING GALVANNEALED STEEL SHEET AND METHOD FOR PRODUCING THE SAME

High-strength galvannealed steel sheet including any of a) an oxide containing Fe and Mn, b) an oxide containing Fe and Mn and an Fe oxide, c) an oxide containing Fe and Mn and a Mn oxide, d) an oxide containing Fe and Mn, an Fe oxide, and a Mn oxide, and e) an Fe oxide and a Mn oxide is present in a zinc coated layer. The total amount of oxide is 0.01 to 0.100 g/m; the ratio by mass % of Mn to Fe, e.g., Mn/Fe, contained in the oxide is 0.10 to 10.00; an oxide of at least one selected from Fe and Mn is present in an amount of 60% or more; and an oxide of at least one selected from Fe and Mn is present in a surface layer portion of a steel sheet in an amount of 0.040 g/mor less (not including zero). 1. A Mn-containing galvannealed steel sheet , comprising a steel sheet containing , on a mass % basis:C: 0.03% to 0.35%;Si: 0.01% to 2.00%;Mn: 3.0% to 8.0%;Al: 0.001% to 1.000%;P: 0.10% or less; and{'sup': '2', 'claim-text': 'wherein the zinc coated layer contains any one of a) to e) described below,', 'S: 0.01% or less, the balance being Fe and incidental impurities, the steel sheet having a zinc coated layer on one or both surfaces thereof with a coating weight of 20 to 120 g/m,'}a) an oxide containing Fe and Mn,b) an oxide containing Fe and Mn and an Fe oxide,c) an oxide containing Fe and Mn and a Mn oxide,d) an oxide containing Fe and Mn, an Fe oxide, and a Mn oxide, and [{'sup': '2', 'a total amount of the oxide is 0.01 to 0.100 g/min terms of an amount of O, a ratio by mass % of Mn to Fe, i.e., Mn/Fe, contained in the oxide is 0.10 to 10.00,'}, 'the oxide of at least one selected from Fe and Mn is present in an amount of 60% or more in terms of a cross-sectional area fraction in a range from a surface of the zinc coated layer to a position 50% or less of a total thickness of the zinc coated layer, and', {'sup': '2', 'an oxide of at least one selected from Fe and Mn is present in a surface layer portion of the steel sheet in an amount of 0.040 g/mor less (not ...

HIGH-STRENGTH PLATED STEEL SHEET HAVING EXCELLENT PLATING PROPERTIES, WORKABILITY, AND DELAYED FRACTURE RESISTANCE, AND METHOD FOR PRODUCING SAME

The high-strength plated steel sheet of the present invention has a plated layer on the surface of a base steel sheet and contains predetermined steel components. The steel sheet includes, in the order from the interface of the base steel sheet and the plated layer towards the base steel sheet: a soft layer having a Vickers hardness that is 90% or less of the Vickers hardness at a portion t/ of the base steel sheet, where t is a sheet thickness of the base steel sheet: and a hard layer containing martensite, bainite, and ferrite in predetermined ranges. The average depth D of the soft layer is 20 μm or greater, and the average depth d of an internal oxide layer is 4 μm or greater and smaller than D. 1. A high-strength plated steel sheet , comprising:a hot-dip galvanized or galvannealed layer on a surface of a base steel sheet, the base steel sheet comprises, in mass %,', 'C: 0.05 to 0.25%;', 'Si: 0.25 to 3%;', 'Mn: 1.5 to 4%;', 'P: more than 0% to 0.1% or less;', 'S: more than 0% to 0.05% or less;', 'Al: 0.005 to 1%; and', 'N: more than 0% to 0.01% or less,', 'the high-strength plated steel sheet sequentiaih has, from an interface of the base steel sheet and the hot-dip galvanized or galvannealed layer towards the base steel sheet:', 'an internal oxide layer containing at least one oxide selected from the group consisting of Si and Mn;', {'b': '4', 'a soft layer including the internal oxide and having a Vickers hardness of 90% less of a Vickers hardness at a portion t/ of the base steel sheet, where t is a sheet thickness of the base steel sheet; and'}, 'a hard layer containing martensite and bainite in a proportion of from 60 area % or more to less than 95 area %, and polygonal ferrite in a proportion of from more than 5 area % to 40 area % or less,, 'wherein'}an average depth D of the soft layer is 20 μm or greater,an average depth d of the internal oxide layer is 4 μm or greater and smaller than the D, andthe high strength plated steel sheet has a tensile ...

HIGH-STRENGTH PLATED STEEL SHEET HAVING EXCELLENT PLATING PROPERTIES, WORKABILITY, AND DELAYED FRACTURE RESISTANCE, AND METHOD FOR PRODUCING SAME

Disclosed herein is a high-strength plated steel sheet having a plated layer on the surface of a base steel sheet and containing predetermined steel components. The steel sheet includes, in the order from the interface of the base steel sheet and the plated layer towards the base steel sheet: a soft layer having a Vickers hardness that is 90% or less of the Vickers hardness at a portion t/4 of the base steel sheet, where t is a sheet thickness of the base steel sheet; and a hard layer consisting of a structure which is mainly composed of martensite and bainite and in which the average grain size of prior austenite is 20 μm or less. The average depth D of the soft layer is 20 μm or greater, and the average depth d of an internal oxide layer is 4 μm or greater and smaller than D. 1. A high-strength plated steel sheet having a hot-dip galvanized layer or a hot-dip galvannealed layer on a surface of a base steel sheet , wherein: C: 0.05 to 0.25%;', 'Si: 0.5 to 2.5%;', 'Mn: 2.0 to 4%;', 'P: more than 0% to 0.1% or less;', 'S: more than 0% to 0.05% or less;', 'Al: 0.01 to 0.1%; and', 'N: more than 0% to 0.01% or less; and, '(1) the base steel sheet comprises, in mass %,'} an internal oxide layer comprising at least one oxide selected from the group consisting of Si and Mn;', 'a soft layer including the internal oxide layer and having a Vickers hardness of 90% or less of a Vickers hardness at a portion t/4 of the base steel sheet, where t is a sheet thickness of the base steel sheet; and', 'a hard layer comprising a structure which is mainly composed of martensite and bainite and in which the average grain size of prior austenite is 20 μm or less,, '(2) the high-strength plated steel sheet sequentially has, from an interface of the base steel sheet and the hot-dip galvanized layer or galvannealed layer, towards the base steel sheet an average depth D of the soft layer being 20 μm or greater; and', 'an average depth d of the internal oxide layer being 4 μm or greater and ...

STEEL SHEET FOR HOT PRESSING AND HOT PRESSED ARTICLE USING THE SAME

A steel sheet for hot pressing includes in a chemical composition, in percent by mass, C of 0.1% to 0.4%, Si of greater than 0% to 2.0%, Mn of 0.5% to 3.0%, P of greater than 0% to 0.015%, S of greater than 0% to 0.01%, F3 of 0.0003% to 0.01%, N of greater than 0% to 0.05%, Al in a content of 2×[N]% to 0.3% at a Si content of greater than 0.5% to 2.0%; or Al in a content of (0.20+2×[N]-0.40×[Si]N)% to 0.3% at a Si content of 0% to 0.5%, where [N] and [Si] are contents of N and Si, respectively, in mass percent, with the remainder being iron and inevitable impurities, where contents of Ti, Zr, Hf, and Ta, of the inevitable impurities, are each controlled to 0.005% or lower. The steel sheet includes nitride-based inclusions with an equivalent circle diameter of 1 μm or more in a number density of 0.10 per square millimeter. 1. A steel sheet for hot pressing , comprising , in a chemical composition:C in a content of 0.1% to 0.4%;Si in a content of 0% to 2.0%;Mn in a content of 0.5% to 3.0%;P in a content of greater than 0% to 0.015%;S in a content of greater than 0% to 0.01%:B in a content of 0.0003% to 0.01%;N in a content of greater than 0% to 0.05%; andAl in a content of 2×[N]% to 0.3% at a Si content of greater than 0.5% to 2.0%; or Al in a content of (0.20+2×[N]-0.40×[Si])% to 0.3% at a Si content of 0% to 0.5%, where [N] and [Si] are contents of N and Si, respectively, in mass percent,with the remainder being iron and inevitable impurities,the steel sheet having contents of Ti, and Ta, of the inevitable impurities, controlled to 0.005% or lower; andthe steel sheet comprising nitride-based inclusions with an equivalent circle diameter of 1 μm or more in a number density of less than 0.10 per square millimeter.3. A hot pressed article having the chemical composition as defined in claim 1 ,the hot pressed article comprising martensite in an area percentage of 90% or higher of an entire microstructure thereof; andthe hot pressed article having a number density of ...

HIGH STRENGTH STEEL SHEET

High strength steel sheet having a tensile strength of 800 MPa or more comprising a middle part in sheet thickness and a soft surface layer arranged at one side or both sides of the middle part in sheet thickness, wherein each soft surface layer has a thickness of more than 10 μM and 30% or less of the sheet thickness, the soft surface layer has an average Vickers hardness of more than 0.60 time and 0.90 time or less the average Vickers hardness of the sheet thickness 1/2 position, and the soft surface layer has a nano-hardness standard deviation of 0.8 or less is provided. 112-. (canceled)13. High strength steel sheet having a tensile strength of 800 MPa or more comprising a middle part in sheet thickness and a soft surface layer arranged at one side or both sides of the middle part in sheet thickness , wherein each soft surface layer has a thickness of more than 10 μm and 30% or less of the sheet thickness , the soft surface layer has an average Vickers hardness of more than 0.60 time and 0.90 time or less the average Vickers hardness of the sheet thickness 1/2 position , and the soft surface layer has a nano-hardness standard deviation of 0.8 or less.14. The high strength steel sheet according to claim 13 , wherein the high strength steel sheet further comprises a hardness transition zone formed between the middle part in sheet thickness and each soft surface layer while adjoining them claim 13 , wherein the hardness transition zone has an average hardness change in the sheet thickness direction of 5000 (ΔHv/mm) or less.15. The high strength steel sheet according to claim 13 , wherein the middle part in sheet thickness comprises claim 13 , by area percent claim 13 , 10% or more of retained austenite.16. The high strength steel sheet according to claim 14 , wherein the middle part in sheet thickness comprises claim 14 , by area percent claim 14 , 10% or more of retained austenite.17. The high strength steel sheet according to claim 13 , wherein the middle part in ...

STEEL SHEET, METHOD OF MANUFACTURING SAME, CROWN CAP, AND DRAWING AND REDRAWING (DRD) CAN

Provided is a steel sheet having sufficient formability and strength even after sheet metal thinning, the steel sheet including: a chemical composition containing, by mass %, C: more than 0.0060% and not more than 0.012%, Si: 0.02% or less, Mn: 0.10% or more and 0.60% or less, P: 0.020% or less, S: 0.020% or less, Al: 0.01% or more and 0.07% or less, and N: 0.0080% or more and 0.0200% or less, with the balance being Fe and inevitable impurities, in which a dislocation density at a depth position of ½ of a sheet thickness from a surface of the steel sheet is 2.0×10/mor more and 1.0×10/mor less. 1. A steel sheet comprising: C: more than 0.006% and not more than 0.012%,', 'Si: 0.02% or less,', 'Mn: 0.10% or more and 0.60% or less,', 'P: 0.020% or less,', 'S: 0.020% or less,', 'Al: 0.01% or more and 0.07% or less, and', 'N: 0.0080% or more and 0.0200% or less,, 'a chemical composition containing, by mass %,'}with the balance being Fe and inevitable impurities; wherein{'sup': 14', '2', '15', '2, 'a dislocation density at a depth position of ½ of a sheet thickness from a surface of the steel sheet is 2.0×10/mor more and 1.0×10/mor less.'}2. The steel sheet according to claim 1 , having a thickness of 0.20 mm or less.3. A crown cap made of the steel sheet as recited in .4. A DRD can made of the steel sheet as recited in .5. A method of manufacturing the steel sheet as recited in claim 1 , comprising:a hot rolling step of heating a steel raw material at 1200° C. or higher, finish rolling the steel raw material to obtain a hot rolled sheet, and then coiling the hot rolled sheet within a temperature range of 670° C. or lower;a pickling step of pickling the hot rolled sheet after the hot rolling step;a primary cold rolling step of cold rolling the hot rolled sheet after the pickling step to obtain a cold rolled sheet;an annealing step of annealing the cold rolled sheet after the primary cold rolling step in a temperature range of 650° C. to 750° C. to obtain an annealed sheet; ...

METHOD OF PRODUCING PRESS-HARDENED AND COATED STEEL PARTS AT A HIGH PRODUCTIVITY RATE

This invention relates to a sheet or pre-coated blank comprising a steel substrate for heat treatment, overlaid on at least a part of at least one of its principal faces, by a pre-coating having, at least one layer of aluminum or aluminum alloy overlaid, on at least a part of the above-mentioned pre-coating, by a polymerized layer having a thickness between 2 and 30 μm composed of a polymer that does not contain silicon, and the nitrogen content of which, is greater than 1% by weight expressed in relation to the above-mentioned layer, wherein the above-mentioned polymerized layer contains carbon pigments in a quantity between 3 and 30% by weight, expressed in relation to said layer. 112310. Sheet or pre-coated blank comprising a steel substrate for heat treatment () overlaid on at least a part of at least one of its main faces by a pre-coating () comprising at least one layer of aluminum or aluminum alloy overlaid on at least a part of the above-mentioned pre-coating by a polymerized layer () having a thickness between 2 μm and 30 μm composed of a polymer that does not contain silicon , and the nitrogen content of which is greater than 1% by weight expressed in relation to the above-mentioned layer , wherein the above-mentioned polymerized layer contains carbon pigments in a quantity between 3 and 30% by weight , expressed in relation to above-mentioned layer.2. Sheet or blank according to claim 1 , characterized in that the elements of said polymer are selected from a list consisting of C claim 1 , H claim 1 , O claim 1 , N.3. Sheet or blank according to claim 1 , characterized in that the polymerized layer is obtained from a resin in the form of a dispersion or emulsion in aqueous phase.4. Sheet or blank according to claim 1 , characterized in that the polymerized layer is obtained from a resin in the form of solution in a non-aqueous solvent.5. Sheet or blank according to claim 1 , characterized in that the polymerized layer is constituted by a film roll-bonded ...

HIGH FORMABILITY DUAL PHASE STEEL

To improve the formability of dual phase steels, the martensite phase is tempered. It may form a ferrite-carbide structure. The tempering step occurs after martensite has been formed in the dual phase steel. The tempering step can occur in a box annealing step or it can be performed in a continuous fashion, such as on a continuous annealing, continuous tempering heat treating, or continuous coating line. The tempering step can further comprise a temper rolling on a temper mill after the heating step. 1. A method of improving the formability of a dual phase steel strip comprising ferrite and martensite , the method comprising the step of temper heat treating the dual phase steel strip at a temperature and for a time sufficient to transform at least a portion of the martensite to ferrite and cementite.2. The method of further comprising the step of temper rolling the dual phase steel after the temper heat treating step.3. The method of wherein the temper heat treating step occurs after the strip has been cold rolled.4. The method of wherein the temper heat treating step occurs after the strip has been coated with a coating.5. The method of wherein the temper heat treating step is a box annealing step.6. The method of wherein the temper heat treating step is a continuous temper heating step.7. The method of wherein the continuous temper heating is provided by induction heating.8. A method of improving the formability of a dual phase steel having a nominal tensile strength of 780 MPa comprising the step of temper heat treating the dual phase steel strip at a temperature for a time such that yield x<110 micrometers.9. The method of wherein the yield x<90 micrometers.10. A method of improving the formability of a dual phase steel having a nominal tensile strength of 980 MPa comprising the step of temper heat treating the dual phase steel strip at a temperature for a time such that yield x<100 micrometers.11. The method of claim 10 , wherein the yield x<10 micrometers.12. ...

PROCESS FOR MANUFACTURING PRESS-HARDENED COATED STEEL PARTS AND PRECOATED SHEETS ALLOWING THESE PARTS TO BE MANUFACTURED

This invention relates to a cold-rolled sheet that is annealed and pre-coated for the fabrication of press hardened parts, composed of a steel substrate for heat treatment with a carbon content Cbetween 0.07% and 0.5%, whereby this content is expressed by weight, and a metal pre-coating on at least the two principal faces of the steel substrate, characterized in that the substrate comprises a decarburized area on the surface of each of the two principal faces, whereby the depth pof the decarburized area is between 6 and 30 micrometers, whereby pis the depth at which the carbon content is equal to 50% of the content C, and in that the sheet does not contain a layer of iron oxide between the substrate and the metal pre-coating.

High strength galvanized steel sheet having excellent bendability and weldability, and method of manufacturing the same

A method of manufacturing a galvanized steel sheet includes a two-stage temperature raising process which includes: primary heating the sheet from 200° C. to an intermediate temperature of 500 to 800° C. at a primary average heating rate of 5 to 50° C./second at an excess air ratio of 1.10 to 1.20 maintained up to the intermediate temperature; secondary heating the sheet from the intermediate temperature to an annealing temperature of 730 to 900° C. at a secondary average heating rate of 0.1 to 10° C./second at an excess air ratio of less than 1.10 maintained up to the annealing temperature; holding the sheet to the annealing temperature for 10 to 500 seconds; cooling the sheet to 450 to 550° C. at an average cooling rate of 1 to 30° C./second; and subjecting the sheet to a galvanizing process and, optionally, an alloying process.

Roller hearth furnace and method for the heat treatment of metal sheets

The invention relates to a roller hearth furnace for the heat treatment of coated metal sheets as well as to a corresponding method. The objective of the invention is to put forward a roller hearth furnace that allows the alternating processing of AlSi-coated metal sheets and metal sheets with zinc alloy coatings for hot-working, whereby considerably less effort is involved for the alternating procedure than is the case in the state of the art. The roller hearth furnace according to the invention for the heat treatment of coated metal parts is characterized in that it has at least a first zone and a second zone, whereby in the first zone, a temperature below the melting temperature of the AlSi deposits or a temperature of more than approximately 900° C. [1652° F.] can be maintained, whereas in the second zone, a temperature of more than approximately 870° C. [1598° F.] can be reached.

HIGH-STRENGTH STEEL SHEET AND PRODUCTION METHOD THEREFOR

A steel sheet has a microstructure that contains ferrite in an area ratio of 20% or more, martensite in an area ratio of 5% or more, and tempered martensite in an area ratio of 5% or more. The ferrite has a mean grain size of 20.0 μm or less. An inverse intensity ratio of γ-fiber to α-fiber in the ferrite is 1.00 or more and an inverse intensity ratio of γ-fiber to α-fiber in the martensite and the tempered martensite is 1.00 or more. 1. A high-strength steel sheet comprising:a chemical composition that contains, by mass %, C: 0.060% or more and 0.200% or less, Si: 0.50% or more and 2.20% or less, Mn: 1.00% or more and 3.00% or less, P: 0.100% or less, S: 0.0100% or less, Al: 0.010% or more and 2.500% or less, N:212-. (canceled)14. The high-strength steel sheet according to claim 1 , wherein the high-strength steel sheet is a cold-rolled steel sheet.15. The high-strength steel sheet according to claim 13 , wherein the high-strength steel sheet is a cold-rolled steel sheet.16. The high-strength steel sheet according to claim 1 , wherein the high-strength steel sheet comprises a coating or plating on a surface thereof.17. The high-strength steel sheet according to claim 13 , wherein the high-strength steel sheet comprises a coating or plating on a surface thereof.18. The high-strength steel sheet according to claim 16 , wherein the coating or plating is a galvanized coating or plating.19. The high-strength steel sheet according to claim 17 , wherein the coating or plating is a galvanized coating or plating.20. A method for producing the high-strength steel sheet according to claim 1 , the method comprising:{'claim-ref': {'@idref': 'CLM-00001', 'claim 1'}, 'heating a steel slab comprising the chemical composition as recited in to a temperature range of 1150° C. to 1300° C.;'}subjecting the steel slab to hot rolling with a finisher delivery temperature from 850° C. to 1000° C. to obtain a hot-rolled steel sheet;subjecting the hot-rolled steel sheet to coiling in a ...

STEEL SHEET FOR HOT PRESS-FORMING, METHOD FOR MANUFACTURING THE SAME, AND METHOD FOR PRODUCING HOT PRESS-FORMED PARTS USING THE SAME

The invention provides a steel sheet for hot press-forming that can reliably give hot press-formed parts having excellent paint adhesiveness, perforation corrosion resistance and joint corrosion resistance, and also provides a method for manufacturing the steel sheet for hot press-forming, and a method for producing hot press-formed parts using the steel sheet for hot press-forming. The steel sheet for hot press-forming includes a base steel sheet and a Zn-based coating layer with a mass of coating of 10 to 90 g/mon the base steel sheet, wherein the average ferrite grain diameter in the surface microstructure of the base steel sheet is not more than 20 μm. 1. A steel sheet for hot press-forming comprising a base steel sheet and a Zn-based coating layer with a mass of coating of 10 to 90 g/mon the base steel sheet , wherein the average ferrite grain diameter in the surface microstructure of the base steel sheet is not more than 20 μm.2. The steel sheet for hot press-forming according to claim 1 , wherein the Zn-based coating layer has a chemical composition comprising 10 to 25 mass % Ni and the balance being Zn and inevitable impurities.3. The steel sheet for hot press-forming according to claim 2 , wherein the Zn-based coating layer includes an η phase in an amount of not more than 5 mass %.4. The steel sheet for hot press-forming according to claim 1 , wherein the base steel sheet under the Zn-based coating layer has a chemical composition comprising claim 1 , by mass % claim 1 , C: 0.15 to 0.5% claim 1 , Si: 0.05 to 2.0% claim 1 , Mn: 0.5 to 3% claim 1 , P: not more than 0.1% claim 1 , 5: not more than 0.05% claim 1 , Al: not more than 0.1% claim 1 , N: not more than 0.01% claim 1 , and the balance being Fe and inevitable impurities.5. The steel sheet for hot press-forming according to claim 4 , wherein the base steel sheet under the Zn-based coating layer further includes claim 4 , by mass % claim 4 , at least one selected from Cr: 0.01 to 1% claim 4 , Ti: not ...

FERRITIC STAINLESS STEEL AND METHOD FOR MANUFACTURING SAME, FERRITIC STAINLESS STEEL SHEET AND METHOD FOR MANUFACTURING SAME, AND FUEL CELL MEMBER

Ferritic stainless steel is characterized by including, by mass %: Cr: 12.0% to 16.0%; C: 0.020% or less; Si: 2.50% or less; Mn: 1.00% or less; P: 0.050% or less; S: 0.0030% or less; Al: 2.50% or less; N: 0.030% or less; Nb: 0.001% to 1.00%; one or more of B: 0.0200% or less, Sn: 0.20% or less, Ga: 0.0200% or less, Mg: 0.0200% or less, and Ca: 0.0100% or less; and a balance consisting of Fe and impurities, in which Expression (1) is satisfied. 1. Ferritic stainless steel , comprising , by mass %:Cr: 12.0% to 16.0%;C: 0.020% or less;Si: 2.50% or less;Mn: 1.00% or less;P: 0.050% or less;S: 0.0030% or less;Al: 2.50% or less;N: 0.030% or less;Nb: 0.001% to 1.00%;Ni: 0% to 1.0%;Cu: 0% to 1.0%;Mo: 0% to 1.0%;Sb: 0% to 0.5%;W: 0% to 1.0%;Co: 0% to 0.5%;V: 0% to 0.5%;Ti: 0% to 0.5%;Zr: 0% to 0.5%;La: 0% to 0.1%;Y: 0% to 0.1%;Hf: 0% to 0.1%;REM: 0 to 0.1%;one or more of B: 0.0200% or less, Sn: 0.20% or less, Ga: 0.0200% or less, Mg: 0.0200% or less, and Ca: 0.0100% or less; and a balance consisting of Fe and impurities, {'br': None, '10(B+Ga)+Sn+Mg+Ca>0.020 \u2003\u2003(1)'}, 'wherein Expression (1) is satisfied,'}where each of the element symbols in Expression (1) indicates the content (mass %) of each of the elements in the steel.2. The ferritic stainless steel according to claim 1 , comprising B: 0.0002% or more by mass %.3. The ferritic stainless steel according to claim 1 , wherein the concentration of Nb at a crystal grain boundary is within a range of 3.0% to 10% by mass %.4. The ferritic stainless steel according to claim 1 , comprising:the concentration of Sn is 0.005% or more by mass %,the concentration of Sn at a crystal grain boundary is 1.0% to 5.0% by mass %.5. The ferritic stainless steel according to claim 1 , comprising claim 1 , by mass %:Si: 0.5% or more;Al: 1% or more; andNb: 0.15% or more.6. The ferritic stainless steel according to claim 1 , comprising claim 1 , by mass % claim 1 , one or more of Ni: 0.10% to 1.0% claim 1 , Cu: 0.10% to 1.0% claim 1 , ...

HOT STAMPING STEEL AND PRODUCING METHOD THEREOF

Disclosed is a steel composition for hot stamping that comprises carbon (C) in an amount of about 0.22 to about 0.25 wt %, silicon (Si) in an amount of about 0.2 to about 0.3 wt %, manganese (Mn) in an amount of about 1.2 to about 1.4 wt %, titanium (Ti) in an amount of about 0.02 to about 0.05 wt %, chromium (Cr) in an amount of about 0.11 to about 0.2 wt %, boron (B) in an amount of about 0.005 to about 0.01 wt %, zinc (Zr) in an amount of about 0.005 to about 0.02 wt %, niobium (Nb) in an amount of about 0.01 to about 0.05 wt %, tungsten (W) in an amount of about 0.1 to about 0.5 wt %, iron (Fe) constituting the remaining balance of the steel composition, all the wt % based on the total amount of the steel composition. 1. A steel composition for hot stamping , comprising:carbon (C) in an amount of about 0.22 to about 0.25 wt %;silicon (Si) in an amount of about 0.2 to about 0.3 wt %;manganese (Mn) in an amount of about 1.2 to about 1.4 wt %;titanium (Ti) in an amount of about 0.02 to about 0.05 wt %;chromium (Cr) in an amount of about 0.11 to about 0.2 wt %;boron (B) in an amount of about 0.005 to about 0.01 wt %;zinc (Zr) in an amount of about 0.005 to about 0.02 wt %;niobium (Nb) in an amount of about 0.01 to about 0.05 wt %;tungsten (W) in an amount of about 0.1 to about 0.5 wt %;iron (Fe) constituting the remaining balance of the steel composition,wherein all the wt % based on the total amount of the steel composition.2. The steel composition for hot stamping of claim 1 , consisting essentially of:carbon (C) in an amount of about 0.22 to about 0.25 wt %;silicon (Si) in an amount of about 0.2 to about 0.3 wt %;manganese (Mn) in an amount of about 1.2 to about 1.4 wt %;titanium (Ti) in an amount of about 0.02 to about 0.05 wt %;chromium (Cr) in an amount of about 0.11 to about 0.2 wt %;boron (B) in an amount of about 0.005 to about 0.01 wt %;zinc (Zr) in an amount of about 0.005 to about 0.02 wt %;niobium (Nb) in an amount of about 0.01 to about 0.05 wt %; ...

Method for Producing a Cold-Rolled Flat Steel Product with High Yield Strength and Flat Cold-Rolled Steel Product

A method for producing a cold-rolled steel strip with a yield ratio Re/Rm of at least 0.7, the cold-rolled steel product including iron, unavoidable impurities and (in wt. %) C: 0.05-0.20%, Si: 0.25-1.00%, Mn: 1.0-3.0%, Al: 0.02-1.5%, Cr: 0.1-1.5%, N: <0.Q2%, P: <0.03%, S: <0.05% and optionally one or more of Ti, Mo, Nb, V, and B, Ti: up to 0.15%, Mo: <2%, Nb: <0.1%, V: <0.12%, and B: 0.0005-0.003%. The cold-rolled flat steel product undergoes heat treatment for 4.5-24 hours at a temperature of 150-400° C. Also, a cold rolled flat steel product discussed above having a structure including at least two phases, selected from (in vol. %) at least 10% tempered martensite, <10% bainite, <10% residual austenite and remainder ferrite, a yield ratio of at least 0.7, a tensile strength of ≧750 MPa and a hole expansion of at least 18%. 1. A method for producing a cold-rolled steel strip , comprising: providing a cold-rolled flat steel product comprising iron , unavoidable production impurities and (in wt. %) C: 0.05-0.20% , Si: 0.25-1.00% , Mn: 1.0-3.0% , Al: 0.02-1.5% , Cr: 0.1-1.5% , N: less than 0.02% , P: less than 0.03% , S: less than 0.05% and optionally one or more elements from the group Ti , Mo , Nb , V , and B subject to Ti: being up to 0.15% , Mo: less than 2% , Nb: less than 0.1% , V: less than 0.12% , and B: 0.0005-0.003% , wherein the cold-rolled flat steel product provided undergoes heat treatment , during which it is annealed for an annealing time of 4.5-24 hours at an annealing temperature of up to 150-400° C. and , after the heat treatment , the cold-rolled flat steel product has a yield ratio Re/Rm of at least 0.7.2. The method according to claim 1 , wherein the annealing time is 6-18 hours.3. The method according to claim 1 ,wherein the cold-rolled flat steel product obtained after the heat treatment has a structure comprising at least two phases selected from at least 10 vol.-% tempered martensite, less than 10 vol.-% bainite, less than 10 vol.-% residual ...

HIGH-STRENGTH PLATED STEEL PLATE FOR WELDED STRUCTURAL MEMBER, AND METHOD FOR PRODUCING THE SAME

A high-strength plated steel plate for a welded structural member having a steel composition containing from 0.050 to 0.150% of C, from 0.001 to 1.00% of Si, from 1.00 to 2.50% of Mn, from 0.005 to 0.050% of P, from 0.001 to 0.020% of S, and from 0.005 to 0.100% of Al, having a steel base material having a metal structure containing a ferrite phase and a second phase containing mainly martensite having an average crystal grain diameter of 8 mm or less, and having a chemical composition and a thickness t (mm) of the steel base material regulated to obtain a value, C/0.2+Si/5.0+Mn/1.3+Cr/1.0+Mo/1.2+0.4t−0.7(Cr+Mo), of 2.9 or less. The high-strength plated steel plate is excellent in corrosion resistance of the welded portion, resistance to liquid metal embrittlement cracking, and bending workability. 2. The high-strength plated steel plate for a welded structural member according to claim 1 , wherein the hot-dip Zn—Al—Mg based alloy plated layer has a composition containing from 3.0 to 22.0% of Al claim 1 , from 0.05 to 10.0% of Mg claim 1 , from 0 to 0.10% of Ti claim 1 , from 0 to 0.05% of B claim 1 , from 0 to 2.0% of Si claim 1 , and from 0 to 2.0% of Fe claim 1 , all in terms of percentage by mass claim 1 , with the balance of Zn and unavoidable impurities.4. The method for producing a high-strength plated steel plate for a welded structural member according to claim 3 , wherein the hot-dip plating bath has a composition containing from 3.0 to 22.0% of Al claim 3 , from 0.05 to 10.0% of Mg claim 3 , from 0 to 0.10% of Ti claim 3 , from 0 to 0.05% of B claim 3 , from 0 to 2.0% of Si claim 3 , and from 0 to 2.0% of Fe claim 3 , all in terms of percentage by mass claim 3 , with the balance of Zn and unavoidable impurities. The present invention relates to a high-strength hot-dip Zn—Al—Mg based alloy plated steel plate for a welded structural member fabricated by arc welding, particularly suitable for an automobile underbody member, and a method for producing the ...

HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME

A high-strength galvanized steel sheet having a chemical composition containing, by mass %, C: 0.07% to 0.25%, Si: 0.01% to 3.00%, Mn: 1.5% to 4.0%, P: 0.100% or less, S: 0.02% or less, Al: 0.01% to 1.50%, N: 0.001% to 0.008%, Ti: 0.003% to 0.200%, B: 0.0003% to 0.0050%, and the balance being Fe and inevitable impurities, in which the relationship Ti>4N is satisfied, and a microstructure including, in terms of area ratio in a cross section located at ¼ of the thickness from the surface of a base steel sheet, a ferrite phase in an amount of 70% or less (including 0%), a bainite phase in an amount of 20% or less (including 0%), a martensite phase in an amount of 25% or more, and a retained austenite phase in an amount of less than 3% (including 0%), in which the average crystal grain diameter of the martensite phase is 20 μm or less, and in which a variation in the Vickers hardness of the martensite phase is 20 or less in terms of standard deviation, as well as a method for manufacturing the steel sheet, is disclosed. 16.-. (canceled)8. The high-strength claim 7 , galvanized steel sheet according to claim 7 , the chemical composition further containing claim 7 , by mass % claim 7 , at least one group selected from the group consisting of Group A to C: Cr: 0.01% to 2.00%,', 'Mo: 0.01% to 2.00%,', 'V: 0.01% to 2.00%,', 'Ni: 0.01% to 2.00%, and', 'Cu: 0.01% to 2.00%;, 'Group A, which contains at least one selected from 'Nb: 0.003% to 0.200%; and', 'Group B, which contains Ca: 0.001% to 0.005%, and', 'REM: 0.001% to 0.005%., 'Group C, which contains at least one selected from9. A method for manufacturing a high-strength claim 7 , galvanized steel sheet claim 7 , the method comprising performing the following processes in the following order:{'claim-ref': {'@idref': 'CLM-00007', 'claim 7'}, 'a hot rolling process in which, after having performed finish rolling on a slab having the chemical composition according to , cooling is performed such that a total time during which ...

High-strength cold-rolled steel sheet and method for manufacturing the same

A steel sheet has a microstructure including ferrite phase: 40% to 60%, bainite phase: 10% to 30%, tempered martensite phase: 20% to 40%, and retained austenite phase: 5% to 20% by volume fraction, and satisfying a condition that a ratio of tempered martensite phase having major axis length ≦5 μm to a total volume fraction of the tempered martensite phase is 80% to 100%.

High-strength galvanized steel sheet and method for producing the same

Provided are a high-strength galvanized steel sheet having excellent delayed fracture resistance by reducing the diffusible hydrogen content in the steel and a method for producing the same. The high-strength galvanized steel sheet includes a steel sheet having a prescribed composition and a microstructure including martensite and tempered martensite, the total area fraction of the martensite and the tempered martensite being 30% or more, and a galvanizing layer formed on the surface of the steel sheet. The diffusible hydrogen content in the high-strength galvanized steel sheet is 0.50 wt. ppm or less. The half-width of the hydrogen release peak of the high-strength galvanized steel sheet is 70° C. or less. The diffusible hydrogen content and the half-width of the hydrogen release peak are determined by a prescribed analysis method.

STEEL, PRODUCT MADE OF SAID STEEL, AND MANUFACTURING METHOD THEREOF

Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mmif hot-formed or hot-rolled; and measuring 800 mmif cold-rolled, does not contain non-metallic inclusions of diameter >10 μm, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 μm over 100 mm, the observation being performed by image analysis over a polished surface measuring 650 mm. 1. Steel , characterised in that its composition , in percentages by weight is as follows:10.0%≤Ni≤24.5%, preferably 12.0%≤Ni≤24.5%;1.0%≤Mo≤12.0%, preferably 2.5%≤Mo≤9.0%;1.0%≤Co≤25.0%;20.0%≤Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≤29.0%, preferably 22.0%≤Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≤29.0%, more preferably 22.5%≤Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≤29.0%;Co+Mo≥20.0%; preferably Co+Mo≥21.0%; more preferably Co+Mo≥22.0%;Ni+Co+Mo≥29%; preferably Ni+Co+Mo≥41.0%;traces ≤Al≤4.0%, preferably 0.01%≤Al≤1.0%;traces ≤Ti≤0.1%;traces ≤N≤0.0050%;traces ≤Si≤2.0%; preferably 0.04%≤Si≤2.0%;traces ≤Mn≤4.0%;traces ≤C≤0.03%;traces ≤S≤0.0020%, preferably traces ≤S≤0.0010%;traces ≤P≤0.005%;traces ≤B≤0.01%;traces ≤H≤0.0005%;traces ≤O≤0.0025%;traces ≤Cr≤5.0%;traces ≤Cu≤2.0%;traces ≤W≤4.0%;traces ≤Zr≤4.0%;traces ≤Ca≤0.1%;traces ≤Mg≤0.1%;traces ≤Nb≤4.0%;traces ≤V≤4.0%;traces ≤Ta≤4.0%;with the remainder being iron and impurities resulting from the smelting and manufacturing process;{'sup': 2', '2', '2', '2, 'and in that the inclusion population, as observed by means of image analysis over a polished surface measuring 650 mmif the steel is in the form of a component part/work piece that is hot-formed or a hot-rolled sheet; and measuring 800 mmif the steel is in the form of a cold-rolled sheet, ...

PROCESS FOR MANUFACTURING A RECOVERY ANNEALED COATED STEEL SUBSTRATE FOR PACKAGING APPLICATIONS AND A PACKAGING STEEL PRODUCT PRODUCED THEREBY

This relates to a process for manufacturing a recovery annealed coated steel substrate for packaging applications and a packaging steel product produced thereby. 1. A process for manufacturing a recovery annealed coated steel substrate for packaging applications , comprising the steps of:{'sub': 'a', 'providing a steel slab or strip suitable for producing a low-carbon, an extra-low-carbon or an ultra-low-carbon hot rolled strip for producing packaging steel by hot rolling at a finishing temperature higher than or equal to the Artransformation point;'}cold-rolling the resulting steel strip to produce a single reduced steel substrate;{'sup': '2', 'electrodepositing a tin layer on one or both sides of the single reduced steel substrate to produce a tin-coated steel substrate, wherein the coating weight of the tin layer or layers onto one or both sides of the substrate is at most 1000 mg/m;'}{'sub': a', 'a, 'claim-text': to convert the tin layer into an iron-tin alloy layer which contains at least 90 weight percent (wt. %) of FeSn (50 at. % iron and 50 at. % tin), and', 'to simultaneously obtain a recovered microstructure and wherein no recrystallisation of the single reduced substrate takes place (i.e. recovery annealing);, 'heating the tin-coated steel substrate at a heating rate exceeding 300° C./s followed by annealing the tin-coated steel substrate at a temperature Tof between 513° C. and 645° C. for an annealing time tfast cooling the annealed substrate at a cooling rate of at least 100° C./s; a carbon content of 0.05% or less;', 'a nitrogen content of 0.004% or less;', 'a manganese content between 0.05 and 0.5%;', 'a phosphorous content of 0.02% or less;', 'a silicon content of 0.02% or less;', 'a sulphur content of 0.03% or less;', 'an aluminum content of 0.1% or less;', a niobium content between 0.001% and 0.1%;', 'a titanium content between 0.001% and 0.15%;', 'a vanadium content between 0.001% and 0.2%;', 'a zirconium content between 0.001% and 0.1%;', 'a ...

HIGH STRENGTH HOT DIP GALVANISED STEEL STRIP

A high strength hot dip galvanized steel strip including, in mass percent, of the following elements: 0.10-0.18% C, 1.90-2.50% Mn, 0.30-0.50% Si, 0.50-0.70% Al, 0.10-0.50% Cr, 0.001-0.10% P, 0.01-0.05% Nb, max 0.004% Ca, max 0.05% S, max 0.007% N, and optionally at least one of the following elements: 0.005-0.50% Ti, 0.005-0.50% V, 0.005-0.50% Mo, 0.005-0.50% Ni, 0.005-0.50% Cu, max 0.005% B, the balance Fe and inevitable impurities, wherein 0.80%2.10%. This steel offers improved formability at a high strength, has a good weldability and surface quality together with a good produce-ability and coat-ability. 2. Steel strip according to claim 1 , wherein element C is present in an amount of 0.13-0.16%.3. Steel strip according to claim 1 , wherein element Mn is present in an amount of 1.95-2.30%.4. Steel strip according to claim 1 , wherein element Si is present in an amount of 0.35-0.45%.5. Steel strip according to claim 1 , wherein element Al is present in an amount of 0.55-0.65%.6. Steel strip according to claim 1 , wherein element Cr is present in an amount of 0.20-0.50%.7. Steel strip according to claim 1 , wherein the element Nb is present in an amount of 0.01-0.04%.8. Steel strip according to claim 1 , wherein the hot dip galvanised steel strip has an ultimate tensile strength of 780 MPa or higher.9. Steel strip according to claim 1 , wherein the hot dip galvanised steel strip has a microstructure consisting of 55-75 volume % ferrite claim 1 , 20-10 volume % bainite claim 1 , 20-10 volume % martensite and 10-5 volume % metastable retained austenite.10. Method for producing a high strength hot dip galvanised steel strip according to claim 1 , wherein the cast steel is hot rolled and cold rolled to a strip having a desired thickness claim 1 , after which the strip is reheated in an annealing line to a temperature between the Ac1 and the Ac3 temperature of the steel type and fast cooled at a cooling rate to avoid retransformation to ferrite ...

Method for producing a component by further forming a preformed contour

In a method for producing a component by further forming of a preformed contour of a blank, the blank which has previously been cut to size at ambient temperature from a strip or a metal sheet undergoes after optional further manufacturing steps carried out at ambient temperature, e.g. punching or cutting operations to realize recesses or openings, in selected edge regions that have been strain hardened by the punching or cutting operations to obtain a preformed contour a first forming operation at ambient temperature. The edge regions intended to undergo the forming operation or at least the edge regions that have undergone the first forming operation are heated to a temperature of at least 600° C. for maximal 10 seconds. After the heat treatment, the edge regions undergo at any time a second forming operation or further forming operations at ambient temperature with respectively preceding heat treatments.

High-strength steel sheet for warm working and method for manufacturing the same

A high-strength steel sheet for warm working having excellent warm workability, and a method for manufacturing the steel sheet. The steel sheet has a chemical composition including, by mass %, C: 0.05% to 0.20%, Si: 3.0% or less, Mn: 3.5% to 8.0%, P: 0.100% or less, S: 0.02% or less, Al: 0.01% to 3.0%, N: 0.010% or less, one or more selected from Nb: 0.005% to 0.20%, Ti: 0.005% to 0.20%, Mo: 0.005% to 1.0%, and V: 0.005% to 1.0%. The steel sheet has a microstructure including, in terms of area ratio, 10% to 60% of retained austenite, 10% to 80% of ferrite, 10% to 50% of martensite, and 0% to 5% of bainite, in which a C content in the retained austenite is less than 0.40 mass % and the average crystal grain diameter of the retained austenite, the martensite, and the ferrite is 2.0 μm or less.

High strength annealed steel products and annealing processes for making the same

The present invention provides steel sheet products having controlled compositions that are subjected to two-step annealing processes to produce sheet products having desirable microstructures and favorable mechanical properties such as high strength and ultra-high formability. The steel sheet products may be cold rolled or hot rolled. Steels processed in accordance with the present invention exhibit favorable combined ultimate tensile strength and total elongation (UTS•TE) properties, and may fall into the category of Generation 3 advanced high strength steels, desirable in various industries including automobile manufacturers.

Method For Producing an Ultra High Strength Galvannealed Steel Sheet and Obtained Galvannealed Steel Sheet

A method for producing a coated steel sheet having a tensile strength TS of at least 1450 MPa and a total elongation TE of at least 17% includes the successive steps of providing a cold rolled steel sheet made of a steel having a chemical composition comprising, in weight %: 0.34%≤C≤0.45%, 1.50%≤Mn≤2.30%, 1.50≤Si≤2.40%, 0% Подробнее

HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR MANUFACTURING THE SAME (AS AMENDED)

A high-strength galvanized steel sheet has a chemical composition containing, by mass %, C: 0.16% or more and 0.24% or less, Si: 0.8% or more and 1.8% or less, Mn: 1.0% or more and 3.0% or less, P: 0.020% or less, S: 0.0040% or less, Al: 0.01% or more and 0.1% or less, N: 0.01% or less, Ca: 0.0001% or more and 0.0020% or less, and the balance including Fe and incidental impurities, and a microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 10% or more and 20% or less, and in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less. 1. A high-strength galvanized steel sheet having a chemical composition containing , by mass % ,C: 0.16% or more and 0.24% or less,Si: 0.8% or more and 1.8% or less,Mn: 1.0% or more and 3.0% or less,P: 0.020% or less,S: 0.0040% or less,Al: 0.01% or more and 0.1% or less,N: 0.01% or less,Ca: 0.0001% or more and 0.0020% or less, andthe balance comprising Fe and incidental impurities, anda microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 10% or more and 20% or less, and in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less.2. A method for manufacturing a high-strength galvanized steel sheet claim 1 , the method comprising hot-rolling a steel slab having the chemical ...

HEAT-ROLLED STEEL PLATE FOR TAILORED ROLLED BLANK, TAILORED ROLLED BLANK, AND METHODS FOR PRODUCING THESE

A heat-rolled steel plate has a chemical composition that contains, in mass %, C, Si, Mn, P, S, Al, N and Ti, and that satisfies Formula (1); and a microstructure containing bainite and ferrite. In the interior of the steel plate an average value of pole densities of an orientation group {100}<011> to {223}<110> is 4 or less, and a pole density of a {332}<113> crystal orientation is 4.8 or less. In an outer layer of the steel plate, a pole density of a {110}<001> crystal orientation is 2.5 or more. Furthermore, among Ti carbo-nitrides in the steel plate, the number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is 1.0×10per cmor less, and a bake hardening amount is 15 MPa or more. 1. A heat-roiled steel plate for a tailored rolled blank comprising:a chemical composition consisting of, in mass %,C: 0.03 to 0.1%,Si: 1.5% or less,Mn: 1.0 to 2.5%,P: 0.1% or less,S: 0.02% or less,Al: 0.01 to 1.2%,N: 0.01% or less,Ti: 0.015 to 0.15%,Nb: 0 to 0.1%,Cu: 0 to 1%,Ni: 0 to 1%,Mo: 0 to 0.2%,V: 0 to 0.2%,Cr: 0 to 1%,W: 0 to 0.5%,Mg: 0 to 0.005%,Ca: 0 to 0.005%,rare earth metal: 0 to 0.1%,B: 0 to 0.005%, andone or more types of element selected from a group consisting of Zr, Sn, Co and Zn in a total amount of 0 to 0.05%, with the balance being Fe and impurities, and satisfying Formula (1); anda microstructure containing, in terms of area ratio, 20% or more of bainite, with 50% or more in terms of area ratio of the balance being ferrite;wherein:at a depth position that is equivalent to one-half of a plate thickness from a surface of the heat-rolled steel plate, an average value of pole densities of an orientation group {100}<011> to {223}<110> comprising crystal orientations {100}<011>, {116}<110>, {114}<110>, {113}<110>, {112}<110>, {335}<110> and {223}<110> is four or less and a pole density of a {332}<113> crystal orientation is 4.8 or less;at a depth position that is equivalent to one-eighth of the plate thickness from the surface of the heat- ...

STEEL SHEET FOR HOT STAMPING AND METHOD FOR PRODUCING STEEL SHEET FOR HOT STAMPING, AND HOT STAMP FORMED BODY

A steel sheet for hot stamping includes a composition including at least, in mass %, C: 0.100% to 0.600%, Si: 0.50% to 3.00%, Mn: 1.20% to 4.00%, Ti: 0.005% to 0.100%, B: 0.0005% to 0.0100%, P: 0.100% or less, S: 0.0001% to 0.0100%, Al: 0.005% to 1.000%, and N: 0.0100% or less, with a balance of Fe and impurities, surface roughness of the steel sheet satisfies Rz>2.5 μm, and 50 mg/mto 1500 mg/mof coating oil is applied to a surface. 1. A steel sheet for hot stamping , comprising a composition containing:in mass %,C: 0.100% to 0.600%;Si: 0.50% to 3.00%;Mn: 1.20% to 4.00%;Ti: 0.005% to 0.100%;B: 0.0005% to 0.0100%;P: 0.100% or less;S: 0.0001% to 0.0100%;Al: 0.005% to 1.000%;N: 0.0100% or less;Ni: 0% to 2.00%;Cu: 0% to 2.00%;Cr: 0% to 2.00%;Mo: 0% to 2.00%;Nb: 0% to 0.100%;V: 0% to 0.100%;W: 0% to 0.100%, anda total of one kind or two or more kinds selected from a group consisting of REM, Ca, Ce and Mg: 0% to 0.0300%,with a balance being Fe and impurities,{'sup': 2', '2, 'wherein surface roughness of the steel sheet satisfies Rz>2.5 μm, and coating oil in an amount of 50 mg/mto 1500 mg/mis applied onto a surface.'}2. The steel sheet for hot stamping according to claim 1 ,wherein an amount of S contained in the coating oil which is applied onto the steel sheet is 5% or less in mass %.3. The steel sheet for hot stamping according to claim 1 ,wherein the composition of the steel sheet contains, in mass %,one kind or two or more kinds selected from a group consisting ofNi: 0.01% to 2.00%,Cu: 0.01% to 2.00%,Cr: 0.01% to 2.00%,Mo: 0.01% to 2.00%,Nb: 0.005% to 0.100%,V: 0.005% to 0.100%, andW: 0.005% to 0.100%.4. The steel sheet for hot stamping according to claim 1 ,wherein the composition of the steel sheet contains, in mass %,a total of 0.0003% to 0.0300% of one kind or two or more kinds selected from the group consisting of REM, Ca, Ce and Mg.5. A method for producing a steel sheet for hot stamping claim 1 , comprising:a step of casting a slab containing,in mass %,C: 0. ...

HIGH-STRENGTH COLD ROLLED STEEL SHEET AND METHOD OF PRODUCING SAME

A high-strength cold rolled steel sheet has both high strength, i.e. a tensile strength of 900 MPa or more, and high workability, i.e. a total elongation of 20% or more, and also has a high yield ratio of 60% or more. The high-strength cold rolled steel sheet comprises: a predetermined chemical composition; and a steel structure having, in area ratio, ferrite: 30% to 75%, martensite: 15% to 40%, and retained austenite: 10% to 30%. In the case where a distribution of crystal grain circularity of the retained austenite is represented by a histogram with a class range of more than 0.1×(n−1) and 0.1×n or less and a class value of 0.1×n (n is an integer from 1 to 10), a mode of the crystal grain circularity of the retained austenite is 0.6 or less. 1. A high-strength cold rolled steel sheet comprising:a chemical composition containing, in mass %,C: 0.15% to 0.35%,Si: 1.0% to 2.0%,Mn: 1.8% to 3.5%,P: 0.020% or less,S: 0.0040% or less,Al: 0.01% to 0.1%, andN: 0.01% or less,with a balance consisting of Fe and inevitable impurities; anda steel structure having, in area ratio,ferrite: 30% to 75%,martensite: 15% to 40%, andretained austenite: 10% to 30%,wherein in the case where a distribution of crystal grain circularity of the retained austenite is represented by a histogram with a class range of more than 0.1×(n−1) and 0.1×n or less and a class value of 0.1×n where n is an integer from 1 to 10, a mode of the crystal grain circularity of the retained austenite is 0.6 or less, and {'br': None, 'i': 'S/L', 'sup': '2', 'circularity=4π'}, 'circularity of each crystal grain of the retained austenite is calculated according to the following formulawhere S is an area of the crystal grain of the retained austenite, and L is a perimeter of the crystal grain of the retained austenite.2. The high-strength cold rolled steel sheet according to claim 1 , comprisinga galvanized layer on a surface thereof.4. The method of producing a high-strength cold rolled steel sheet according to claim ...

Hot-stamped steel, cold-rolled steel sheet and method for producing hot-stamped steel

A hot-stamped steel according to the present invention has a predetermined chemical composition, satisfies (5×[Si]+[Mn])/[C]>10 when [C] is the amount of C by mass %, [Si] is the amount of Si by mass %, and [Mn] is the amount of Mn by mass %, includes 40% to 95% ferrite and 5% to 60% martensite in area fraction, and optionally further includes 10% or less pearlite in area fraction, 5% or less retained austenite in volume fraction, and less than 40% bainite in area fraction. The total of the area fraction of ferrite and the area fraction of martensite is 60% or more, the hardness of martensite measured with a nanoindenter satisfies H 2 /H 1 <1.10 and σHM<20, and TS×λ which is product of tensile strength TS and hole expansion ratio λ is 50000 MPa·% or more.

HIGH-STRENGTH GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING THE SAME

A steel sheet and a method for producing the steel sheet are provided. The steel sheet is provided having a composition including C: 0.05% to 0.15%, Si: 0.1% or less, Mn: 1.0% to 2.0%, P: 0.10% or less, S: 0.030% or less, Al: 0.10% or less, and N: 0.010% or less, and including one or two or more of Ti, Nb, and V, the remainder being iron and incidental impurities. The steel sheet has a microstructure containing, on an area percent basis, ferrite: 80% or more, and bainite and martensite: 1% to 20% in total. The ferrite has an average grain size of 10.0 μm or less, and a phase containing bainite and martensite has an average grain size of 3.0 μm or less. The ratio of the average grain size of the phase containing bainite and martensite to the average grain size of the ferrite is 0.3 or less. 1. A high-strength hot-dip galvanized steel sheet with a composition and a microstructure ,wherein the composition includes, on a mass percent basis,C: 0.05% to 0.15%,Si: 0.1% or less,Mn: 1.0% to 2.0%,P: 0.10% or less,S: 0.030% or less,Al: 0.10% or less, andN: 0.010% or less,and includes one or two or more of Ti, Nb, and V satisfying a formula (1), a remainder being iron and incidental impurities,the microstructure contains, on an area percent basis, ferrite: 80% or more, andbainite and martensite: 1% to 20% in total,the ferrite has an average grain size of 10.0 μm or less,a phase containing bainite and martensite has an average grain size of 3.0 μm or less, and {'br': None, '0.008%≤12×(Ti/48+Nb/93+V/51)≤0.05%\u2003\u2003(1)'}, 'a ratio of the average grain size of the phase containing bainite and martensite to the average grain size of the ferrite is 0.3 or less,'}where Ti, Nb, and V denote their respective contents (% by mass), and in the absence of Ti, Nb, or V, the corresponding content is 0.2. The high-strength hot-dip galvanized steel sheet according to claim 1 , wherein the composition further includes claim 1 , on a mass percent basis claim 1 , at least one selected from ...

PROCESS FOR MAKING COATED COLD-ROLLED DUAL PHASE STEEL SHEET

A coated dual-phase steel and process for producing the coated dual-phase steel is provided. The process includes providing a steel slab with a desired chemistry, soaking the slab at an elevated temperature and then hot rolling the slab to produce hot-rolled strip. The hot-rolled strip is coiled and has a ferrite-pearlite microstructure. The coiled hot-rolled strip is cold-rolled into cold-rolled sheet with at least a 60% reduction in thickness compared to the thickness of the coiled hot-rolled strip. The cold-rolled sheet is subjected to an intercritical anneal followed by rapid cooling with the absence of an isothermal heat treatment or hold after rapid cooling near the molten metal pot temperature—during which, before or after which the steel is coated. The coated steel sheet has a dual-phase ferrite-martensite microstructure, a yield strength of at least 310 MPa, a tensile strength of at least 580 MPa and a total elongation to failure of at least 18%. 1. A process for producing a coated dual-phase steel , the process comprising:providing a steel slab with a chemical composition within the range, in weight percent, of 0.085-0.11 C, 1.4-2.0 Mn, 0.19-0.21 Mo, 0.02-0.05 Al, 0.16-0.5 Si, 0.13-0.5 Cr, 0.016 max Ti, 0.06 max Ni, 0.003 max S, 0.015 max P, 0.006 max N, balance Fe and incidental melting impurities;soaking the steel slab at temperatures between 1160-1280° C.;hot rolling the steel slab into hot-rolled strip;coiling the hot rolled strip at temperatures between 600-680° C., the coiled hot rolled strip having a ferrite-pearlite microstructure;cold-rolling the coiled hot-rolled strip into cold-rolled sheet, the cold-rolled sheet having at least a 60% reduction in thickness compared to the thickness of the coiled hot-rolled strip;intercritical annealing the cold-rolled sheet at temperatures between 780-820° C.;rapidly cooling the intercritically annealed cold-rolled sheet to a temperature between 500-520° C. without a hold treatment; andpassing the rapidly ...

HIGH-STRENGTH COLD ROLLED STEEL SHEET AND METHOD OF PRODUCING SAME

A high-strength cold rolled steel sheet has both high strength, i.e. a tensile strength of 900 MPa or more, and high workability, i.e. a total elongation of 20% or more, and also has a low yield ratio of less than 60%. The high-strength cold rolled steel sheet comprises: a predetermined chemical composition; and a steel structure having, in area ratio, ferrite: 30% to 75%, martensite: 15% to 40%, and retained austenite: 10% to 30%. In the case where a distribution of crystal grain circularity of the retained austenite is represented by a histogram with a class range of more than 0.1×(n−1) and 0.1×n or less and a class value of 0.1×n (n is an integer from 1 to 10), a mode of the crystal grain circularity of the retained austenite is 0.7 or more. 1. A high-strength cold rolled steel sheet comprising:a chemical composition containing, in mass %,C: 0.15% to 0.35%,Si: 1.0% to 2.0%,Mn: 1.8% to 3.5%,P: 0.020% or less,S: 0.0040% or less,Al: 0.01% to 0.1%, andN: 0.01% or less,with a balance consisting of Fe and inevitable impurities; anda steel structure having, in area ratio,ferrite: 30% to 75%,martensite: 15% to 40%, andretained austenite: 10% to 30%,wherein in the case where a distribution of crystal grain circularity of the retained austenite is represented by a histogram with a class range of more than 0.1×(n−1) and 0.1×n or less and a class value of 0.1×n where n is an integer from 1 to 10, a mode of the crystal grain circularity of the retained austenite is 0.7 or more, and {'br': None, 'i': 'S/L', 'sup': '2', 'circularity=4π'}, 'circularity of each crystal grain of the retained austenite is calculated according to the following formulawhere S is an area of the crystal grain of the retained austenite, and L is a perimeter of the crystal grain of the retained austenite.2. The high-strength cold rolled steel sheet according to claim 1 , comprisinga galvanized layer on a surface thereof.3. A method of producing a high-strength cold rolled steel sheet claim 1 , the method ...

HIGH STRENGTH ANNEALED STEEL PRODUCTS

The present invention provides steel sheet products having controlled compositions that are subjected to two-step annealing processes to produce sheet products having desirable microstructures and favorable mechanical properties such as high strength and ultra-high formability. Steels processed in accordance with the present invention exhibit combined ultimate tensile strength and total elongation (UTS·TE) properties of greater than 25,000 MPa-%. Steels with these properties fall into the category of Generation 3 advanced high strength steels, and are highly desired by various industries including automobile manufacturers. 1. A high strength cold rolled steel sheet product comprising from 0.12 to 0.5 weight percent C , from 1 to 3 weight percent Mn , and from 0.8 to 3 weight percent of a combination of Si and Al , wherein the steel sheet product has been subjected to a two-step annealing process , comprises ferrite and substantially equiaxed retained austenite grains having an average aspect ratio of less than 3:1 , and has a combination of ultimate tensile strength and total elongation UTS·TE of greater than 25 ,000 MPa %.2. The high strength cold rolled steel sheet product of claim 1 , wherein the Si comprises up to 2 weight percent claim 1 , the Al comprises up to 2 weight percent claim 1 , and the further steel sheet product further comprises up to 0.05 weight percent Ti claim 1 , and up to 0.05 weight percent Nb.3. The high strength cold rolled steel sheet product of claim 2 , wherein the C comprises from 0.15 to 0.4 weight percent claim 2 , the Mn comprises from 1.3 to 2.5 weight percent claim 2 , the Si comprises from 0.2 to 1.8 weight percent claim 2 , the Al comprises up to 1.5 weight percent claim 2 , the Ti comprises up to 0.03 weight percent claim 2 , and the Nb comprises up to 0.03 weight percent.4. The high strength cold rolled steel sheet product of claim 2 , wherein the C comprises from 0.17 to 0.35 weight percent claim 2 , the Mn comprises from 1.5 ...

METHOD FOR ROLLING AND/OR HEAT TREATING A METAL STRIP

The invention relates to a method for rolling a metal product (), wherein the metal product is subjected to a rolling operation at a first station (), which rolling operation is controlled by a control device (), wherein the product () is subject to a measurement at a second station (), wherein the product () is subjected to a further processing operation at a third station (), and wherein the product () is in a specified quality at a fourth station (). In order to increase the quality of the produced strip, the invention provides that the method has the following steps: a) measuring the value of a material property (IW) that the second station (); b) feeding the value measured at the second station () to the control device (), comparing the measured value with a value (SW) stored in the control device (), and adjusting a parameter (PPI) if the measured value deviates from the stored value (SW), e) measuring a value of a quality material property (Q) at the fourth station (); d) comparing the measured value with a stored value, and initiating a measure to influence the quality material property (Q) if the measured value deviates from the stored value beyond a permissible tolerance 1112314251641761. A method of rolling and/or heat treating a metallic product () , in particular a strip or sheet , wherein the product () is subjected at a first position () to a rolling and/or heat treating operation which is controlled and/or regulated by a control device and/or regulating device () , wherein the product () is subjected at a second position () downstream from the first position () to a measuring by a measuring device () , wherein the product () is subjected at a third position () downstream from the second position () to another working operation , and wherein the product () is present at a fourth position () downstream from the third position () in a given quality , wherein the quality of the product is characterized by the quality-material property (Q) of the product ...

High-Strength Hot-Dip Galvanized Steel Sheet Excellent in Impact Resistance Property and Manufacturing Method Thereof, and High-Strength Alloyed Hot-Dip Galvanized Steel Sheet and Manufacturing Method Thereof

A base steel sheet has a hot-dip galvanized layer formed on a surface thereof, in which, in a steel sheet structure in a range of ⅛ thickness to ⅜ thickness centered around ¼ thickness of a sheet thickness from a surface, a volume fraction of a retained austenite phase is 5% or less, and a total volume fraction of phases of bainite, bainitic ferrite, fresh martensite, and tempered martensite is 40% or more, an average effective crystal grain diameter is 5.0 μm or less, a maximum effective crystal grain diameter is 20 μm or less, and a decarburized layer with a thickness of 0.01 μm to 10.0 μm is formed on a surface layer portion, in which a density of oxides dispersed in the decarburized layer is 1.0×10 12 to 1.0×10 16 oxides/m 2 , and an average grain diameter of the oxides is 500 nm or less.

HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCING THE SAME

There is provided a high-strength steel sheet having a tensile strength (TS) of 900 MPa or more and excellent elongation, stretch flangeability, and bendability in a component system in which an expensive alloy element is not intentionally added. A high-strength steel sheet includes a composition including, on a mass % basis, C: 0.15 to 0.40%, Si: 1.0 to 2.0%, Mn: 1.5 to 2.5%, P: 0.020% or less, S: 0.0040% or less, Al: 0.01 to 0.1%, N: 0.01% or less, and Ca: 0.0020% or less, with the balance including Fe and incidental impurities. The high-strength steel sheet has a microstructure including 40% to 70% of a ferrite phase and a bainite phase in total, 20% to 50% of a martensite phase, and 10% to 30% of a retained austenite phase in terms of an area fraction relative to the entire microstructure. 1. A high-strength steel sheet comprising a composition including , on a mass % basis:C: 0.15 to 0.40%,Si: 1.0 to 2.0%,Mn: 1.5 to 2.5%,P: 0.020% or less,S: 0.0040% or less,Al: 0.01 to 0.1%,N: 0.01% or less, andCa: 0.0020% or less, with the balance comprising Fe and incidental impurities, wherein the high-strength steel sheet has a microstructure including 40% to 70% of a ferrite phase and a bainite phase in total, 20% to 50% of a martensite phase, and 10% to 30% of a retained austenite phase in terms of an area fraction relative to the entire microstructure.2. The high-strength steel sheet according to claim 1 , wherein a surface of the high-strength steel sheet is coated with a zinc-based coating layer.3. A method for producing a high-strength steel sheet claim 1 , comprising hot-rolling and pickling a steel slab having the composition in ; then performing a first heat treatment in which the resulting sheet is heated to a temperature range of 400° C. to 750° C.; then cold-rolling the resulting sheet; then performing a second heat treatment in which the resulting sheet is heated to a temperature range of 800° C. to 950° C.; and then performing a third heat treatment in which ...

HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET AND METHOD FOR PRODUCING THE SAME

A high-strength hot-dip galvanized steel sheet includes a hot-dip galvanized layer on a surface of the steel sheet and has a specific component composition and a steel microstructure containing, on an area percentage basis, 90% to 100% of martensite and carbide-containing bainite in total and 0% to 10% of retained austenite, and containing prior austenite grains having an aspect ratio of 2.0 or less, in a region extending from 300 μm to 400 μm from the surface layer, in which the ratio of the average amount of C at 5 μm from the surface layer to the average amount of C at 70 μm from the surface layer is 0.2 to 0.8, and the ratio of the standard deviation of the amount of C to the average amount of C in a region extending from 300 μm to 400 μm from the surface layer is 0.40 or less. 1. A high-strength hot-dip galvanized steel sheet , comprising:a hot-dip galvanized layer on a surface of the steel sheet;a component composition containing, on a percent by mass basis:C: 0.12% to 0.35%,Si: 0.01% to 3.0%,Mn: 2.0% to 4.0%,P: 0.100% or less (excluding 0),S: 0.02% or less (excluding 0), andAl: 0.01% to 1.50%, the balance being Fe and incidental impurities; anda steel microstructure containing, on an area percentage basis, 90% to 100% of martensite and carbide-containing bainite in total and 0% to 10% of retained austenite, and containing prior austenite grains having an aspect ratio of 2.0 or less, in a region extending from a position 300 μm to a position 400 μm from the surface layer of the steel sheet in a thickness direction,wherein a ratio of an average amount of C at a position 5 μm from the surface layer of the steel sheet in the thickness direction to an average amount of C at a position 70 μm from the surface layer of the steel sheet in the thickness direction is 0.20 to 0.80, anda ratio of a standard deviation of an amount of C to an average amount of C when analysis is performed with an FE-EPMA in a region extending from a position 300 μm to a position 400 μm from ...

Ferritic stainless steel having excellent high-temperature oxidation resistance, and manufacturing method therefor

Disclosed are a ferritic stainless steel capable of inhibiting high temperature oxidation through generation of an effective oxide scale, and manufacturing method thereof. The ferritic stainless steel excellent in oxidation resistance at high temperature according to an embodiment of the present disclosure includes, in percent (%) by weight of the entire composition, Cr: 10 to 30%, Si: 0.2 to 1.0%, Mn: 0.1 to 2.0%, W: 0.3 to 2.5%, Ti: 0.001 to 0.15%, Al: 0.001 to 0.1%, the remainder of iron (Fe) and other inevitable impurities, and satisfies a following equation (1). W/(Ti+Al)≥10  (1)

STEEL, PRODUCT MADE OF SAID STEEL, AND MANUFACTURING METHOD THEREOF

Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mmif hot-formed or hot-rolled; and measuring 800 mmif cold-rolled, does not contain non-metallic inclusions of diameter >10 μm, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 μm over 100 mm, the observation being performed by image analysis over a polished surface measuring 650 mm. 132-. (canceled)33. Steel , wherein its composition , in percentages by weight is as follows:10.0%≦Ni≦24.5%, preferably 12.0%≦Ni≦24.5%;1.0%≦Mo≦12.0%, preferably 2.5%≦Mo≦9.0%;1.0%≦Co≦25.0%;20.0%≦Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≦29.0%, preferably 22.0%≦Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≦29.0%, more preferably 22.5%≦Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C≦29.0%;Co+Mo≧20.0%; preferably Co+Mo≧21.0%; more preferably Co+Mo≧22.00;Ni+Co+Mo≧29%; preferably Ni+Co+Mo≧41.00;traces≦Al≦4.0%, preferably 0.01%≦Al≦1.00;traces≦Ti≦0.10;traces≦N≦0.0050%;traces≦Si≦2.0%; preferably 0.04%≦Si≦2.0%;traces≦Mn≦4.00;traces≦C≦0.030;traces≦S≦0.0020%, preferably traces≦S≦0.00100;traces≦P≦0.0050;traces≦B≦0.010;traces≦H≦0.0005%;traces≦O≦0.0025%;traces≦Cr≦5.00;traces≦Cu≦2.00;traces≦W≦4.00;traces≦Zr≦4.00;traces≦Ca≦0.10;traces≦Mg≦0.10;traces≦Nb≦4.00;traces≦V≦4.00;traces≦Ta≦4.00;with the remainder being iron and impurities resulting from the smelting and manufacturing process;{'sup': 2', '2', '2', '2, 'and in that the inclusion population, as observed by means of image analysis over a polished surface measuring 650 mmif the steel is in the form of a component part/work piece that is hot-formed or a hot-rolled sheet; and measuring 800 mmif the steel is in the form of a cold-rolled sheet, does not contain non ...

Plated steel sheet for hot press forming having excellent impact property, hot press formed part, and manufacturing method thereof

Provided is a plated steel sheet for hot press forming, having an excellent impact property, including: a base steel sheet comprising, by wt %, 0.15-0.4% of C, 0.05-1.0% of Si, 0.6-3.0% of Mn, 0.001-0.05% of P, 0.0001-0.02% of S, 0.01-0.1% of Al, 0.001-0.02% of N, 0.001-0.01% of B, 0.01-0.5% of Cr, 0.01-0.05% of Ti, and the balance of Fe and inevitable impurities; and an Al—Si plated layer formed on the surface of the base steel sheet. A thickness of a carbon-depleted layer in a surface layer part of the base steel sheet is 5 μm or less. The surface layer part means a region from the surface of the base steel sheet to a depth of 200 μm, and the carbon-depleted layer means a region which the carbon content is 50% or less of an average carbon amount (C0) of the base steel sheet.

HIGH STRENGTH COLD ROLLED STEEL SHEET AND HIGH STRENGTH GALVANIZED STEEL SHEET HAVING EXCELLENT DUCTILITY AND BENDABILITY, AND METHODS FOR PRODUCING SAME

Provided is a high strength cold rolled steel sheet having a tensile strength of 980 MPa or higher and excellent ductility and bendability. The high strength cold rolled steel sheet has a specified component composition. The structures at a position of ¼ sheet thickness in the steel sheet has certain area ratio of ferrite relative to the entire structure, certain area ratio of a mixed structure of fresh martensite and retained austenite relative to the entire structure, certain region in which the concentration of Mn is enriched, certain standard deviation of the fraction of a region in which the concentration of Mn is enriched, and certain concentration of Mn in a ferrite phase. 1. A high strength cold rolled steel sheet having a tensile strength of 980 MPa or higher and excellent ductility and bendability ,the steel sheet satisfying a component composition comprising in percent by mass:C: 0.10% to 0,30%,Si: 1.2% to 3%;Mn: 0.5% to 3.0%;P: more than 0% to 0.1% or less;S: more than 0% to 0.05% or less;Al: 0.005% to 0.2%;N: more than 0% to 0.01% or less; andO: more than 0% to 0.01% or less,the balance being iron and inevitable impurities, and structures at a position of ¼ sheet thickness in the steel sheet satisfying all of (1) to (5) below:(1) the area ratio of ferrite relative to the entire structure is from 5% or more to less than 50%, and the balance is a hard phase, when observed under a scanning electron microscope;(2) the area ratio of a mixed structure of fresh martensite and retained austenite relative to the entire structure is more than 0% to 30% or less, when observed under an optical microscope after LePera etching;(3) a region in which the concentration of Mn is enriched to 1.2 times or more the concentration of Mn in the steel sheet is present at 5 area% or more, when analyzed with an electron probe microanalyzer;(4) when the fraction of a region in which the concentration of Mn is enriched to 1.2 times or more the concentration of Mn in the steel sheet ...

METHOD FOR THE HOT FORMING OF A STEEL COMPONENT

A method for hot forming a steel component is provided. The steel component is heated into a range of complete or partial austenitization in a heat treatment step. The heated steel component is both hot-formed and quench-hardened in a forming step. A first pretreatment step precedes the heat treatment step in terms of process, in which first pretreatment step the steel component is provided with a corrosion-resistant protective layer in order to protect against scaling in the heat treatment step. Before the heat treatment step is performed, a surface oxidation process occurs in a second pre-treatment step, in which a weakly reactive, corrosion-resistant oxidation layer is formed on the scale protection layer by means of which oxidation layer abrasive tool wear is reduced in the forming step. 1. A method comprising:hot forming a steel component heated into a range of complete or partial austenitization in a heat treatment step;performing a forming step in which the heated steel component is both hot-formed and quench-hardened;performing a first pretreatment step that precedes the heat treatment step in terms of process, in the first pretreatment step the steel component is provided with a corrosion-resistant anti-scale layer to protect against scaling in the heat treatment step; andperforming a second pretreatment step before the heat treatment step so that a surface oxidation process occurs in the second pretreatment step in which surface oxidation process a weakly reactive corrosion-resistant oxidation layer is formed on the anti-scale layer such that abrasive tool wear is reduced in the forming step.2. The method according to claim 1 , wherein the surface oxidation in the second pretreatment step is carried out by pickling passivation claim 1 , and wherein claim 1 , for the pickling passivation claim 1 , the steel component is treated in a pickling bath with a pickling solution and then dried.3. The method according to claim 2 , wherein the pickling solution is an ...

Al or al alloy-coated stainless steel sheet and method of manufacturing ferritic stainless steel sheet

Provided is an Al or Al alloy-coated stainless steel sheet having a coating substrate and a hot-dip Al or Al alloy coated layer provided on a surface of the coating substrate, the coating substrate having a predetermined chemical composition, the Mo content and W content of the chemical composition of the coating substrate, the thickness of the coating substrate, and the thickness of the hot-dip Al or Al alloy coated layer satisfying predetermined relations.

High-formability and super-strength hot galvanizing steel plate and manufacturing method thereof

A high-formability, super-high-strength, hot-dip galvanized steel plate, the chemical composition of which comprises, based on weight percentage, C: 0.15-0.25 wt %, Si: 1.00-2.00 wt %, Mn: 1.50-3.00 wt %, P≦0.015 wt %, S≦0.012 wt %, Al: 0.03-0.06 wt %, N≦0.008 wt %, and the balance of iron and unavoidable impurities. The room temperature structure of the steel plate comprises 10-30% ferrite, 60-80% martensite and 5-15% residual austenite. The steel plate has a yield strength of 600-900 MPa, a tensile strength of 980-1200 MPa, and an elongation of 15-22%. Through an appropriate composition design, a super-high-strength, cold rolled, hot-dip galvanized steel plate is manufactured by continuous annealing, wherein no expensive alloy elements are added; instead, remarkable increase of strength along with good plasticity can be realized just by appropriate augment of Si, Mn contents in combination with suitable processes of annealing and furnace atmosphere control. In addition, the steel plate possesses good galvanization quality that meets the requirement of a super-high-strength, cold rolled, hot-dip galvanized steel plate for automobiles.

HIGH-YIELD-RATIO, HIGH-STRENGTH COLD-ROLLED STEEL SHEET AND PRODUCTION METHOD THEREFOR

A high-yield-ratio, high-strength cold-rolled steel sheet has a composition containing, in terms of % by mass, C: 0.13% to 0.25%, Si: 1.2% to 2.2%, Mn: 2.0% to 3.2%, P: 0.08% or less, S: 0.005% or less, Al: 0.01% to 0.08%, N: 0.008% or less, Ti: 0.055% to 0.130%, and the balance being Fe and unavoidable impurities. The steel sheet has a microstructure that contains 2% to 15% of ferrite having an average crystal grain diameter of 2 um or less in terms of volume fraction, 5 to 20% of retained austenite having an average crystal grain diameter of 0.3 to 2.0 μm in terms of volume fraction, 10% or less (including 0%) of martensite having an average grain diameter of 2 μm or less in terms of volume fraction, and the balance being bainite and tempered martensite, and the bainite and the tempered martensite having an average crystal grain diameter of 5 μm or less. 16.-. (canceled)7. A high-yield-ratio , high-strength cold-rolled steel sheet having a composition and a microstructure ,the steel sheet comprising, in terms of % by mass, C: 0.13% to 0.25%, Si: 1.2% to 2.2%, Mn: 2.0% to 3.2%, P: 0.08% or less, S: 0.005% or less, Al: 0.01% to 0.08%, N: 0.008% or less, Ti: 0.055% to 0.130%, and the balance being Fe and unavoidable impurities,the microstructure comprising 2% to 15% of ferrite having an average crystal grain diameter of 2 μm or less in terms of volume fraction, 5 to 20% of retained austenite having an average crystal grain diameter of 0.3 to 2.0 urn in terms of volume fraction, 10% or less (including 0%) of martensite having an average grain diameter of 2 μm or less in terms of volume fraction, and the balance being bainite and tempered martensite, and the bainite and the tempered martensite having an average crystal grain diameter of 5 μm or less.8. The cold-rolled steel sheet according to claim 7 , wherein the composition further comprises claim 7 , in terms of % by mass claim 7 , B: 0.0003% to 0.0050%.9. The cold-rolled steel sheet according to claim 7 , wherein ...

VERY HIGH-STRENGTH, COLD-ROLLED, DUAL STEEL SHEETS

The present invention provides a cold-rolled and annealed Dual-Phase steel sheet having a tensile strength from 980 to 1100 MPa. The composition includes the contents being expressed by weight: 0.055%≤C≤0.095%, 2%≤Mn≤2.6%, 0.005%≤Si≤0.35%, S≤0.005%, P≤0.050%, 0.1≤Al≤0.3%, 0.05%≤Mo≤0.25%, 0.2%≤Cr≤0.5%, Cr+2 Mo≤0.6%, Ni≤0.1%, 0.010≤Nb≤0.040%, 0.010≤Ti≤0.050%, 0.0005≤B≤0.0025%, and 0.002%≤N≤0.007%. The remainder of the composition includes iron and inevitable impurities resulting from the smelting. A microstructure of the steel sheet is 40 to 65% ferrite, 35 to 50% martensite and 0 to 10% bainite. A non-recrystallized ferrite fraction is less than or equal to 15%. 1. A cold-rolled and annealed Dual-Phase steel sheet comprising: 0.055%≤C≤0.095%;', '2%≤Mn≤2.6%;', '0.005%≤Si≤0.35%;', 'S≤0.005%;', 'P≤0.050%;', '0.1≤Al≤0.3%;', '0.05%≤Mo≤0.25%;', '0.2%≤Cr≤0.5%;', 'Cr+2Mo≤0.6%;', 'Ni≤0.1%;', '0.010≤Nb≤0.040%;', '0.010≤Ti≤0.050%;', '0.0005≤B≤0.0025%; and', '0.002% ≤N≤0.007%;', 'a remainder of the composition comprising iron and the inevitable impurities resulting from smelting;, 'a composition comprising, the contents being expressed by weighta tensile strength between 980 and 1100 MPa; anda microstructure consisting of 40 to 65% ferrite, 35 to 50% martensite and 0 to 10% bainite, a non-recrystallized ferrite fraction being less than or equal to 15%.2. The steel sheet as recited in claim 1 , wherein the composition of the steel contains claim 1 , the content being expressed by weight: 0.12%≤Al≤0.25%.3. The steel sheet as recited in claim 1 , wherein the composition of the steel contains claim 1 , the content being expressed by weight: 0.10%≤Si≤0.30%.4. The steel sheet as recited in claim 1 , wherein the composition of the steel contains claim 1 , the content being expressed by weight: 0.15%≤Si≤0.28%.5. The steel sheet as recited in claim 1 , wherein the composition of the steel contains claim 1 , the content being expressed by weight: P≤0.015%.6. The steel sheet as recited in ...

STEEL SHEET FOR ELECTROPLATING, ELECTROPLATED STEEL SHEET, AND METHODS FOR PRODUCING THE SAME

A steel sheet for electroplating includes, by mass %, C: 0.0005% to 0.0050%, Si: 0.20% to 1.0%, Mn: 0.40% to 2.5%, P: 0.05% or less, Ti: 0.010% to 0.050%, Nb: 0.010% to 0.040%, B: 0.0005% to 0.0030%, S: 0.02% or less, Al: 0.01% to 0.30%, N: 0.0010% to 0.01%, and the balance including Fe and impurities, in which when Si content is represented by [Si] and Mn content is represented by [Mn], “[Mn]+5[Si]” is 2.0 to 7.0, and the steel sheet has surface property in which an average of displacements of a measurement point obtained based on a moving average of continuous 31 points in total including 15 front points and 15 back points in a cross-sectional profile of a surface obtained by measuring the average of displacements in an evaluation length of 10 μm or more at an interval of 0.07 μm, is 0.005 μm to 0.10 μm. 1. A steel sheet for electroplating comprising , as a chemical composition , by mass % ,C: 0.0005% to 0.0050%,Si: 0.20% to 1.0%,Mn: 0.40% to 2.5%,P: 0.05% or less,Ti: 0.010% to 0.050%,Nb: 0.010% to 0.040%,B: 0.0005% to 0.0030%,S: 0.02% or less,Al: 0.01% to 0.30%,N: 0.0010% to 0.01%, andthe balance including Fe and impurities,wherein in the chemical composition, when a Si content is represented by [Si] and a Mn content is represented by [Mn], a value of “[Mn]+5[Si]” is 2.0 to 7.0, andthe steel sheet has a surface property in which an average of displacements of a measurement point that is obtained based on a moving average of continuous 31 points in total including 15 front points and 15 back points in a cross-sectional profile of a surface of the steel sheet obtained by measuring the average of displacements in an evaluation length of 10 μm or more at an interval of 0.07 μm is 0.005 μm to 0.10 μm.2. An electroplated steel sheet , wherein{'claim-ref': {'@idref': 'CLM-00001', 'claim 1'}, 'an electroplating layer is formed on the surface of the steel sheet for electroplating according to .'}3. A method for producing a steel sheet for electroplating , the method ...

METHOD FOR DIRECTLY PRODUCING PICKLING-FREE HOT-PLATED SHEET STRIP PRODUCT FROM MOLTEN STEEL

Method for directly producing a pickling-free hot-plated sheet strip product from molten steel comprising: obtaining a refined molten steel; thin strip continuous casting: a mixed gas of an inert gas and a reducing gas is used for protection in the billet casting process; hot rolling: the cast strip is levelled at a high temperature so as to improve the sheet shape and rolled to a suitable thickness so as to change the product specification, or provide a mechanical disruption action on the iron oxide skin on the surface of the cast strip; reduction annealing: a sectional reduction method is used to perform sectional reductions with the temperature held within two ranges, i.e., 450-600° C. and 700-1000° C., wherein the reduction is performed within a range of 450-600° C. for 1-5 minutes and within a range of 700-1000° C. for 1-3 minutes to remove the iron oxide skin produced in the previous procedure, the concentration of the reducing gas being not lower than 5%; and hot galvanization: after having been cooled in a protective atmosphere, the strip billet is brought into a zinc bath and hot-plated with zinc and other alloy, and then cooled and coiled. The present invention realizes a highly continuous production of a hot-plated product from molten steel with iron and steel, and hot plating with zinc or an alloy is directly performed without removing elementary iron produced by the reduction, so that the energy consumption in the middle stage can be saved and the recovery of metal reaches close to 100%. 1. A method for producing a pickling-free hot-plated sheet strip product directly from molten steel , characterized by comprising the following steps:smelting and refining to obtain a refined molten steel;thin strip continuous casting: after adjusting via a steel ladle and a tundish, the refined molten steel is solidified as a strip billet under the cooling action of a twin-roll strip casting machine in a closed melting pool, and the billet casting process is performed ...

MARTENSITIC STAINLESS-STEEL SHEET AND METAL GASKET

Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of γmax, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less AlO, 20 to 60 mass % SiO, and 15 to 70 mass % MnO. 1. A martensitic stainless hot-rolled steel sheet having a steel composition that comprises , in terms of mass % , 0.030 to 0.300% C , 0.20 to 2.50% Si , 0.15 to 4.00% Mn , 0.01 to 1.00% Ni , 11.00 to 15.00% Cr , 0.001 to 0.100% N , 0.0001 to 0.0350% Al , 0 to 0.50% V , 0 to 0.50% Nb , 0 to 0.50% Ti , 0 to 0.020% B , and a balance of Fe and inevitable impurities , and that has a value of γmax , which is determined by a following equation (1) , of 80.0 or greater , and in which an average composition of oxide based inclusions observed in a metallographic structure has 30 mass % or less AlO , 20 to 60 mass % SiOand 15 to 70 mass % MnO in terms of mass ratio conversion of AlO , SiOand MnO:{'br': None, 'γmax=420C−11.5Si+7Mn+23Ni−11.5Cr−49(Ti+Nb+V)−52Al+470N+189 \u2003\u2003(1)'}herein, a place of the element symbol in the equation (1) is assigned with a content of the corresponding element denoted in terms of mass %.2. The martensitic stainless hot-rolled steel sheet according to claim 1 , wherein in the steel composition claim 1 , any one of following equations (A) and (B) is satisfied:{'br': None, 'Si+Mn≧1.30 and 0.25≦Si/Mn≦1.50 \u2003\u2003(A)'}{'br': None, ' ...

Plated steel sheet for hot press forming having excellent impact property, hot press formed part, and manufacturing method thereof

Provided is a plated steel sheet for hot press forming, having an excellent impact property, including: a base steel sheet comprising, by wt %, 0.15-0.4% of C, 0.05-1.0% of Si, 0.6-3.0% of Mn, 0.001-0.05% of P, 0.0001-0.02% of S, 0.01-0.1% of Al, 0.001-0.02% of N, 0.001-0.01% of B, 0.01-0.5% of Cr, 0.01-0.05% of Ti, and the balance of Fe and inevitable impurities; and an Al—Si plated layer formed on the surface of the base steel sheet. A thickness of a carbon-depleted layer in a surface layer part of the base steel sheet is 5 μm or less. The surface layer part means a region from the surface of the base steel sheet to a depth of 200 μm, and the carbon-depleted layer means a region which the carbon content is 50% or less of an average carbon amount (C0) of the base steel sheet.

COLD-ROLLED STEEL SHEET

A cold-rolled steel according to the present invention has a predetermined chemical composition, satisfies (5×[Si]+[Mn])/[C]>10 when [C] is the amount of C by mass %, [Si] is the amount of Si by mass %, and [Mn] is the amount of Mn by mass %, includes 40% to 95% ferrite and 5% to 60% martensite in area fraction, and optionally further includes 10% or less pearlite in area fraction, 5% or less retained austenite in volume fraction, and less than 40% bainite in area fraction. The total of the area fraction of ferrite and the area fraction of martensite is 60% or more, the hardness of martensite measured with a nanoindenter satisfies H2/H1<1.10 and σHM<20. 2. The cold-rolled steel sheet according to claim 1 , whereinan area fraction of MnS existing in the cold-rolled steel sheet and having an equivalent circle diameter of 0.1 μm to 10 μm is 0.01% or less, {'br': None, 'i': n', 'n, '20/10<1.5\u2003\u2003(J), and'}, 'a following expression (J) is satisfied,'}{'sup': 2', '2, 'the n10 is an average number density per 10000 μmof the MnS having an equivalent circle diameter of 0.1 μm to 10 μm in a ¼ portion of the sheet thickness, and the n20 is an average number density per 10000 μmof the MnS having an equivalent circle diameter of 0.1 μm to 10 μm in the central portion of the sheet thickness.'}3. The cold-rolled steel sheet according to claim 1 , wherein a hot-dip galvanized layer is formed on a surface thereof.4. The cold-rolled steel sheet according to claim 3 , wherein the hot-dip galvanized layer is alloyed.5. The cold-rolled steel sheet according to claim 1 , wherein an electrogalvanized layer is formed on a surface thereof.6. The cold-rolled steel sheet according to claim 1 , wherein an aluminized layer is formed on a surface thereof.7. The cold-rolled steel sheet according to claim 2 , wherein a hot-dip galvanized layer is formed on a surface thereof.8. The cold-rolled steel sheet according to claim 7 , wherein the hot-dip galvanized layer is alloyed.9. The cold- ...

HOT STAMP MOLDED BODY, AND METHOD FOR PRODUCING HOT STAMP MOLDED BODY

A hot stamp molded body that can be produced highly efficiently without causing sticking of plating to a mold, when an electrogalvanized steel sheet with a light plating weight is hot-stamped using a rapidly heating method such as Joule heating and induction heating, and can secure favorable paint adhesiveness without a posttreatment such as shotblasting after hot stamping, as well as a method for producing the same. A hot stamp molded body is produced by hot-stamping an electrogalvanized steel sheet which is composed of predetermined components, and is electrogalvanized on each face with a plating weight not less than 5 g/mand less than 40 g/m; and therein a galvanized layer of the hot stamp molded body is configured with 0 g/mto 15 g/mof a Zn—Fe intermetallic compound and a Fe—Zn solid solution phase as a balance, and in the galvanized layer of the hot stamp molded body 1×10 pcs to 1×10pcs of particulate matter with an average diameter of from 10 nm to 1 μm are present per 1 mm length of the galvanized layer. 1. A hot stamp molded body produced by hot-stamping an electrogalvanized steel sheet , the steel sheet comprising , by mass %:C: from 0.10 to 0.35%,Si: from 0.01 to 3.00%,Al: from 0.01 to 3.00%,Mn: from 1.0 to 3.5%,P: from 0.001 to 0.100%,S: from 0.001 to 0.010%,N: from 0.0005 to 0.0100%,Ti: from 0.000 to 0.200%,Nb: from 0.000 to 0.200%,Mo: from 0.00 to 1.00%,Cr: from 0.00 to 1.00%,V: from 0.000 to 1.000%,Ni: from 0.00 to 3.00%,B: from 0.0000 to 0.0050%,Ca: from 0.0000 to 0.0050%, andMg: from 0.0000 to 0.0050%, [{'sup': 2', '2, 'wherein the steel sheet is electrogalvanized on each face with a plating weight not less than 5 g/mand less than 40 g/m;'}, {'sup': 2', '2, 'wherein a galvanized layer of the hot stamp molded body is configured with 0 g/mto 15 g/mof a Zn—Fe intermetallic compound and a Fe—Zn solid solution phase as a balance, and'}, {'sup': '4', 'wherein, in the galvanized layer of the hot stamp molded body, 1×10 pcs to 1×10pcs of particulate matter ...

High-strength steel sheet, high-strength hot-dip galvanized steel sheet, high-strength hot-dip aluminum-coated steel sheet, and high-strength electrogalvanized steel sheet, and methods for manufacturing same

A high-strength steel sheet with excellent formability and high yield ratio that has TS of 590 MPa or more and YR of 68% or more is obtained by providing a predetermined chemical composition and a steel microstructure that contains, in area ratio, 35 to 80% of polygonal ferrite, 5% or more of non-recrystallized ferrite, and 5 to 25% of martensite, and that contains, in volume fraction, 8% or more of retained austenite, in which the polygonal ferrite has a mean grain size of 6 μm or less, the martensite has a mean grain size of 3 μm or less, the retained austenite has a mean grain size of 3 μm or less, and a value obtained by dividing an Mn content in the retained austenite (in mass %) by an Mn content in the polygonal ferrite (in mass %) equals 2.0 or more.

HIGH-STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING SAME

Disclosed is a steel sheet having a predetermined chemical composition and a steel microstructure that contains, in area ratio, 35% or more and 80% or less of polygonal ferrite and 5% or more and 25% or less of martensite, and that contains, in volume fraction, 8% or more of retained austenite, in which the polygonal ferrite, the martensite, and the retained austenite have a mean grain size of 6 μm or less, 3 μm or less, and 3 μm or less, respectively, and each have a mean grain aspect ratio of 2.0 or less, and in which a value obtained by dividing an Mn content in the retained austenite in mass % by an Mn content in the polygonal ferrite in mass % equals 2.0 or more. 1. A high-strength steel sheet comprising:a chemical composition containing, in mass %, C: 0.030% or more and 0.250% or less, Si: 0.01% or more and 3.00% or less, Mn: 2.60% or more and 4.20% or less, P: 0.001% or more and 0.100% or less, S: 0.0001% or more and 0.0200% or less, N: 0.0005% or more and 0.0100% or less, and Ti: 0.003% or more and 0.200% or less, and the balance consisting of Fe and incidental impurities; anda steel microstructure that contains, in area ratio, 35% or more and 80% or less of polygonal ferrite and 5% or more and 25% or less of martensite, and that contains, in volume fraction, 8% or more of retained austenite,wherein the polygonal ferrite has a mean grain size of 6 μm or less, the martensite has a mean grain size of 3 μm or less, the retained austenite has a mean grain size of 3 μm or less, and the polygonal ferrite, the martensite, and the retained austenite each have a mean grain aspect ratio of 2.0 or less, andwherein a value obtained by dividing an Mn content in the retained austenite in mass % by an Mn content in the polygonal ferrite in mass % equals 2.0 or more.2. The high-strength steel sheet according to claim 1 , wherein the chemical composition further contains claim 1 , in mass % claim 1 , at least one selected from the group consisting of Al: 0.01% or more and 2. ...

STEEL SHEET FOR SOFT-NITRIDING TREATMENT, METHOD OF MANUFACTURING SAME, AND SOFT-NITRIDED STEEL

Provided is a steel sheet for soft-nitriding treatment which has a chemical composition consisting of, in mass %, C: more than or equal to 0.02% and less than 0.07%, Si: less than or equal to 0.10%, Mn: 1.1 to 1.8%, P: less than or equal to 0.05%, S: less than or equal to 0.01%, Al: 0.10 to 0.45%, N: less than or equal to 0.01%, Ti: 0.01 to 0.10%, Nb: 0 to 0.1%, Mo: 0 to 0.1%, V: 0 to 0.1%, Cr: 0 to 0.2%, and the balance: Fe and impurities, satisfies [Mn+Al>1.5], and has a total content of Ti, Nb, Mo, V, and Cr present as precipitates in the steel sheet of less than 0.03% in mass %. The steel sheet for soft-nitriding treatment has a metal structure in which a ferrite area ratio is more than or equal to 80%, and a ferrite dislocation density at a position of 50 μm from a surface of the steel sheet is 1×10to 1×10m. 1. A steel sheet for soft-nitriding treatment which C: more than or equal to 0.02% and less than 0.07%,', 'Si: less than or equal to 0.10%,', 'Mn: 1.1 to 1.8%,', 'P: less than or equal to 0.05%,', 'S: less than or equal to 0.01%,', 'Al: 0.10 to 0.45%,', 'N: less than or equal to 0.01%,', 'Ti: 0.01 to 0.10%,', 'Nb: 0 to 0.1%,', 'Mo: 0 to 0.1%,', 'V: 0 to 0.1%,', 'Cr: 0 to 0.2%, and', 'the balance: Fe and impurities,, 'has a chemical composition consisting of, in mass %,'}satisfies the following formula (i), andhas a total content of Ti, Nb, Mo, V, and Cr present as precipitates in the steel sheet of less than 0.03% in mass %,{'sup': 14', '16', '−2, 'claim-text': {'br': None, 'Mn+Al≧1.5 \u2003\u2003(i)'}, 'wherein the steel sheet for soft-nitriding treatment has a metal structure in which a ferrite area ratio is more than or equal to 80%, and a ferrite dislocation density at a position of 50 μm from a surface of the steel sheet is 1×10to 1×10m,'}where each chemical symbol included in the formula represents a content (mass %) of each element contained in the steel sheet.2. The steel sheet for soft-nitriding treatment according to claim 1 , Nb: 0.005 to 0.1%,', ...

Hot stamped steel

A hot stamped steel includes a base material that is formed of steel, a plated layer that is formed on a surface of the base material, and a phosphate coating that is formed on a surface of the plated layer; chemical composition of the plated layer contains 20.00 to 45.00 mass % of Al, 10.00 to 45.00 mass % of Fe, 4.50 to 15.00 mass % of Mg, 0.10 to 3.00 mass % of Si, 0.05 to 3.00 mass % of Ca, 0 to 0.50 mass % of Sb, 0 to 0.50 mass % of Pb, 0 to 1.00 mass % of Cu, 0 to 1.00 mass % of Sn, 0 to 1.00 mass % of Ti, 0 to 0.50 mass % of Sr, 0 to 1.00 mass % of Cr, 0 to 1.00 mass % of Ni, and 0 to 1.00 mass % of Mn with a remainder of Zn and impurities; the phosphate coating consists of zinc phosphate crystals containing 5.0 to 50.0 mass % of Mg and 0.5 to 5.0 mass % of Ca; and the adhesion amount of the phosphate coating per one surface is in a range of 0.1 to 10.0 g/m2.

STEEL SHEET, PLATED STEEL SHEET, METHOD OF PRODUCTION OF HOT-ROLLED STEEL SHEET, METHOD OF PRODUCTION OF COLD-ROLLED FULL HARD STEEL SHEET, METHOD OF PRODUCTION OF STEEL SHEET, AND METHOD OF PRODUCTION OF PLATED STEEL SHEET

A steel sheet, a plated steel sheet, and methods for producing a hot-rolled steel sheet, a cold-rolled full hard steel sheet, and a steel sheet. The steel sheet has a specified composition and a microstructure including 0 to 80% of polygonal ferrite and 20 to 100% of a total of martensite, bainite, and residual austenite in terms of an area ratio within 20 μm of the steel sheet surface. The content of Mn in martensite present within 20 μm of the steel sheet surface ([Mn]) and the content of Mn in a bulk ([Mn]) satisfy [Mn]/[Mn]≤1.5. At a location 300 μm from the steel sheet surface, an area ratio of the martensite is in a range of 20 to 50%. 1. A steel sheet having a chemical composition comprising , by mass:C: 0.05 to 0.25%;Si: 1.0% or less;Mn: 1.5 to 4.0%;P: 0.100% or less;S: 0.02% or less;Al: 1.0% or less;N: 0.001 to 0.015%;at least one element selected from the group consisting of Ti: 0.003 to 0.100%, Nb: 0.003 to 0.100%, and Mo: 0.005 to 0.500%; andthe balance being Fe and unavoidable impurities, the steel sheet has a microstructure comprising polygonal ferrite in a range of 0 to 80%, and a total of martensite, bainite, and residual austenite in a range of 20 to 100%, in terms of an area ratio in a range of 20 μm in a sheet thickness direction from a surface of the steel sheet,', {'sub': SM', 'B', 'SM', 'B, 'the content of Mn in martensite present in the range of 20 μm in the sheet thickness direction from the surface of the steel sheet ([Mn]) and the content of Mn at a position of ¼-thickness of the steel sheet toward a center in the sheet thickness direction from the surface of the steel sheet ([Mn]) satisfy [Mn]/[Mn]≤1.5, and'}], 'whereinat a location 300 μm in the sheet thickness direction from the surface of the steel sheet, an area ratio of the martensite is in a range of 20 to 50%.2. The steel sheet according to claim 1 , wherein the chemical composition further comprises claim 1 , by mass % claim 1 , at least one element selected from the group ...

Steel, for Hot Forming or Quenching in a Tool, having Improved Ductility

The invention relates to a steel part, the composition of the steel of which comprises, the contents being expressed by weight: 0.040%≦C≦0.100%; 0.80%≦Mn≦2.00%; Si≦0.30%; S≦0.005%; P≦0.030%; 0.010%≦Al≦0.070%; 0.015%≦Nb≦0.100%; 0.030%≦Ti≦0.080%; N≦0.009%; Cu≦0.100%; Ni≦0.100%; Cr≦0.100%; Mo≦0.100%; and Ca≦0.006%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the steel consisting of at least 75% equiaxed ferrite, martensite in an amount not less than 5% but not exceeding 20%, and bainite in an amount not exceeding 10%.

Method for Producing an Ultra High Strength Coated or Not Coated Steel Sheet and Obtained Sheet

A method for producing a cold rolled steel sheet having a tensile strength≧1470 MPa and a total elongation TE≧19%, the method comprising the steps of annealing at an annealing temperature AT≧Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%≦C≦0.40%, 1.50%≦Mn≦2.30%, 1.50≦Si≦2.40%, 0%≦Cr≦0.7%, 0%≦Mo≦0.3%, 0.01%≦Al≦0.07%, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT<Ms transformation point and between 150° C. and 250° C., and making a partitioning treatment by re-heating the quenched steel sheet to a partitioning temperature PT between 350° C. and 420° C. and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 250 seconds.

HIGH-YIELD-RATIO HIGH-STRENGTH COLD-ROLLED STEEL SHEET AND METHOD OF PRODUCING THE SAME

A high-strength cold-rolled steel sheet has a composite structure containing 0.15 to 0.25% by mass of C, 1.8 to 3.0% by mass of Mn, and 0.0003 to 0.0050% by mass of B, and having a ferrite volume fraction of 20% to 50%, a retained austenite volume fraction of 7% to 20%, a martensite volume fraction of 1% to 8%, and the balance containing bainite and tempered martensite, and in the composite structure, ferrite has an average crystal grain diameter of 5 μm or less, retained austenite has an average crystal grain diameter of 0.3 to 2.0 μm and an aspect ratio of 4 or more, martensite has an average crystal grain diameter of 2 μm or less, a metal phase containing both bainite and tempered martensite has an average crystal grain diameter of 7 μm or less, the ratio of the volume fraction of tempered martensite to the volume fraction of a metal structure other than ferrite is 0.60 to 0.85, and the average C concentration in retained austenite is 0.65% by mass or more. 13.-. (canceled)4. A high-yield-ratio high-strength cold-rolled steel sheet having a steel composition comprising , by % by mass , 0.15 to 0.25% of C , 1.2 to 2.2% of Si , 1.8 to 3.0% of Mn , 0.08% or less of P , 0.005% or less of S , 0.01 to 0.08% of Al , 0.007% or less of N , 0.005 to 0.050% of Ti , 0.0003 to 0.0050% of B , and the balance composed of Fe and inevitable impurities , {'br': None, 'i': ≦V', 'V, '0.602/1≦0.85 \u2003\u2003(1).'}, 'wherein the steel sheet has a composite structure having a ferrite volume fraction of 20% to 50%, a retained austenite volume fraction of 7% to 20%, a martensite volume fraction of 1% to 8%, and the balance containing bainite and tempered martensite, and in the composite structure, ferrite has an average crystal grain diameter of 5 μm or less, retained austenite has an average crystal grain diameter of 0.3 to 2.0 μm and an aspect ratio of 4 or more, martensite has an average crystal grain diameter of 2 μm or less, a metal phase containing both bainite and tempered ...

Method for Producing a Stainless Steel Sheet with Modified Visual Characteristics

The invention relates to a method for producing a patterned stainless steel sheet with modified visual characteristics in the wavelength area of visible light the deformed stainless steel having a thickness of 0.3-3.5 mm. In the method the deformed stainless steel sheet is pretreated by at least one heat treatment step and at least one mechanical treatment step on at least one surface of the heat treated stainless steel sheet. The pretreated stainless steel sheet is further transferred for patterning process, and at least one heat treatment step is carried out for the patterned stainless steel sheet surface. 1. A method for producing a patterned stainless steel sheet with improved visual characteristics in the wavelength area of visible light from a deformed stainless steel having a thickness of 0.3-3.5 mm , comprising the steps of: preheating the deformed stainless steel sheet by at least one heat treatment step and at least one mechanical treatment step on at least one surface of the heat treated stainless steel sheet , transferring the pretreated stainless steel sheet for patterning process , where the emboss depth is up to 100 micrometre , and at least one heat treatment step is carried out for the patterned stainless steel sheet.2. The method according to claim 1 , wherein the heat treatment for the deformed stainless steel sheet is carried on at the temperature range 900-1200° C. claim 1 , preferably at the temperature range 1150-1200° C.3. The method according to claim 1 , wherein the heat treatment for the deformed stainless steel sheet is carried out as an annealing and pickling process.4. The method according to claim 1 , wherein the heat treatment for the deformed stainless steel sheet is carried out as a bright annealing process.5. The method according to claim 1 , wherein the mechanical treatment step before the patterning process is carried out by skin-pass rolling.6. The method according to claim 1 , wherein the mechanical treatment step before the ...

BASE MATERIAL FOR HIGH-TOUGHNESS CLAD STEEL PLATE AND METHOD OF PRODUCING THE CLAD STEEL PLATE

A base metal for a high-toughness clad plate has a shear area of 85% or more in a −20° C. DWTT test and includes, in terms of % by mass, C: 0.030% to 0.10%, Si: 0.10% to 0.30%, Mn: 1.30% to 1.80%, P: 0.015% or less, S: 0.003% or less, Mo: 0.05% to 0.50%, V: less than 0.010%, Nb: 0.010% to 0.060%, Ti: 0.005% to 0.020%, Al: 0.040% or less, Ca: 0.0010% to 0.0040%, N: 0.0030% to 0.0060%, and the balance being Fe and unavoidable impurities. 16-. (canceled)7. A base metal for a high-toughness clad plate , the base metal having a shear area of 85% or more in a −20° C. DWTT test and comprising , in terms of % by mass , C: 0.030% to 0.10% , Si: 0.10% to 0.30% , Mn: 1.30% to 1.80% , P: 0.015% or less , S: 0.003% or less , Mo: 0.05% to 0.50% , V: less than 0.010% , Nb: 0.010% to 0.060% , Ti: 0.005% to 0.020% , Al: 0.040% or less , Ca: 0.0010% to 0.0040% , N: 0.0030% to 0.0060% , and the balance being Fe and unavoidable impurities.8. The base metal according to claim 7 , further comprising claim 7 , in terms of % by mass claim 7 , at least one selected from Ni: 0.10% to 0.50% claim 7 , Cr: 0.01% to 0.50% claim 7 , and Cu: 0.005% to 0.050%.9. The base metal according to claim 7 , wherein a ratio of Ti content to N content claim 7 , Ti/N claim 7 , in terms of % by mass is 2.0 to 3.5.10. The base metal according to claim 7 , wherein a ratio of Nb content to C content claim 7 , Nb/C claim 7 , in terms of % by mass is 0.2 to 2.0.11. A clad plate having the base metal according to .12. A method of manufacturing a high-toughness base metal for a clad plate having a shear area of 85% or more in a −20° C. DWTT test claim 7 , comprising clad-rolling the base metal according to and a cladding material claim 7 , performing heating to 900° C. to 1100° C. to conduct a solution treatment claim 7 , and performing a tempering treatment at a temperature less than 550° C.13. The base metal according to claim 8 , wherein a ratio of Ti content to N content claim 8 , Ti/N claim 8 , in terms of % by ...

METHOD FOR MANUFACTURING HIGH-STRENGTH GALVANIZED STEEL SHEET (AS AMENDED)

A method for manufacturing a high-strength galvanized steel sheet includes performing hot rolling, cold rolling, first annealing, pickling, and second annealing. The first annealing is performed to obtain a steel sheet having a steel microstructure including ferrite in an amount of 10% or more and 60% or less in terms of area ratio, and martensite, bainite, and retained austenite in a total amount of 40% or more and 90% or less in terms of area ratio. The second annealing includes heating to an annealing temperature of 750° C. or higher and 850° C. or lower, holding at the annealing temperature for 10 seconds or more and 500 seconds or less, cooling at an average cooling rate of 1° C./s or more and 15° C./s or less, performing a galvanizing treatment, and cooling to a temperature of 150° C. or lower at an average cooling rate of 5° C./s or more and 100° C./s or less. 1. A method for manufacturing a high-strength galvanized steel sheet , the method comprising performing hot rolling on a steel slab having a chemical composition containing , by mass % , C: 0.120% or more and 0.180% or less , Si: 0.01% or more and 1.00% or less , Mn: 2.20% or more and 3.50% or less , P: 0.001% or more and 0.050% or less , S: 0.010% or less , sol.Al: 0.005% or more and 0.100% or less , N: 0.0001% or more and 0.0060% or less , Nb: 0.010% or more and 0.100% or less , Ti: 0.010% or more and 0.100% or less , and the balance being Fe and inevitable impurities in order to obtain a hot-rolled steel sheet , performing cold rolling on the hot-rolled steel sheet in order to obtain a cold-rolled steel sheet , then performing first annealing on the cold-rolled steel sheet , performing pickling on the annealed steel sheet , and then performing second annealing on the pickled steel sheet in order to obtain a galvanized steel sheet , wherein the first annealing includes performing heating to an annealing temperature of 780° C. or higher and 850° C. or lower at an average heating rate of 1° C./s or less ...

METHOD OF PRODUCING ALLOY STRIP LAMINATE AND APPARATUS FOR PRODUCING ALLOY STRIP LAMINATE

This disclosure provides a method of producing an alloy strip laminate including applying an external force directly to an alloy strip of a first laminate member having an adhesive layer and the alloy strip, to form a crack in the alloy strip and prepare a first laminate including the adhesive layer and the cracked alloy strip, applying an external force directly to an alloy strip of a second laminate member having an adhesive layer and the alloy strip, to form a crack in the alloy strip and prepare at least one second laminate including the adhesive layer and the cracked alloy strip, and laminating the at least one second laminate on the first laminate to prepare an alloy strip laminate in which the adhesive layer, and the alloy strip with the crack formed are alternately layered; and a production apparatus for an alloy strip laminate. 122.-. (canceled)23. A method of producing an alloy strip laminate , comprising:applying an external force directly to an alloy strip of a first laminate member, the first laminate member comprising an adhesive layer and the alloy strip, to form a crack in the alloy strip and prepare the first laminate comprising the adhesive layer and the alloy strip with the crack formed therein;applying an external force directly to an alloy strip of a second laminate member, the second laminate member comprising an adhesive layer and the alloy strip, to form a crack in the alloy strip and prepare at least one second laminate comprising the adhesive layer and the alloy strip with the crack formed therein; andlaminating the at least one second laminate on the first laminate to prepare an alloy strip laminate in which the adhesive layers, and the alloy strips with the crack formed therein are alternately layered.24. The method of producing an alloy strip laminate according to claim 23 , wherein preparing the at least one second laminate comprises:adhering the alloy strip to an adhesive layer of a cracking tape, the cracking tape comprising the ...

METHOD OF PRODUCING PRESS-HARDENED AND COATED STEEL PARTS AT A HIGH PRODUCTIVITY RATE

A fabrication method for a press hardened part is provided. A sheet or a steel substrate blank for heat treatment is provided. A pre-coating is applied. The pre-coating has at least one layer of aluminum or aluminum alloy in contact with the steel substrate on at least one of the principal faces of the sheet or blank. Then a polymerized layer is deposited on the pre-coating. The polymerized layer has a thickness between 2 and 30 μm. The polymerized layer does not contain silicon, has a nitrogen content of less than 1% by weight and carbon pigments in a quantity between 3 and 30% by weight. The blank or the sheet is heated to obtain an interdiffusion between the steel substrate and the pre-coating and to give the steel a partly or totally austenitic structure. Then the blank or the sheet is hot stamped to obtain a part. The part is cooled by holding the part in a stamping tool so that the microstructure of the steel substrate includes, at least in a portion of the part, martensite or bainite. 1. A fabrication method for a press hardened part comprising the steps of:providing a sheet or a steel substrate blank for heat treatment;applying a pre-coating having at least one layer of aluminum or aluminum alloy in contact with the steel substrate on at least one of the principal faces of the sheet or blank; thendepositing on the pre-coating, a polymerized layer having a thickness between 2 and 30 μm and comprising a polymer that does not contain silicon, a nitrogen content of less than 1% by weight and carbon pigments in a quantity between 3 and 30% by weight; thenheating the blank or the sheet to obtain an interdiffusion between the steel substrate and the pre-coating and to give the steel a partly or totally austenitic structure, thenhot stamping the blank or the sheet to obtain a part; thencooling the part by holding the part in a stamping tool so that the microstructure of the steel substrate includes, at least in a portion of the part, martensite or bainite.2. The ...

METHOD FOR MANUFACTURING STEEL PLATES

Provided is a method for manufacturing a steel plate that includes plastic working as preliminary processing before press working and is capable of keeping the press formability of the steel plate after the preliminary processing. A method for manufacturing a steel plate used for press working, and the method includes: preparing a steel plate containing C: 0.03 to 0.50 mass % and Mn: 2.0 to 20 mass % and having a ratio of residual austenite in a metallographic structure that is 20 to 50 volume %; and plastic working at least a part of the prepared steel plate while heating the steel plate at 50° C. or higher for preliminary processing before press working. 1. A method for manufacturing a steel plate used for press working , the method comprising:preparing a steel plate containing C: 0.03 to 0.50 mass % and Mn: 2.0 to 20 mass % and having a ratio of residual austenite in a metallographic structure that is 20 to 50 volume %; andplastic working at least a part of the prepared steel plate while heating the steel plate at 50° C. or higher for preliminary processing before press working.2. The method for manufacturing the steel plate according to claim 1 , wherein the plastic working for the preliminary processing rolls the prepared steel plate to have different plate thicknesses. The present application claims priority from Japanese patent application JP 2018-212680 filed on Nov. 13, 2018, the content of which is hereby incorporated by reference into this application.The present disclosure relates to a method for manufacturing a steel plate used for press working.Conventionally pressed components have been manufactured by press working of a blank, such as a steel plate. JP 2012-148305 A, for example, proposes a press-working method based on deformation-induced transformation to transform residual austenite into martensite during plastic working. This press-working method heats a steel material containing 5 volume % or more of residual austenite in the temperature range ...

SPOT WELDED JOINT USING HIGH STRENGTH AND HIGH FORMING STEEL AND ITS PRODUCTION METHOD

The present invention provides a spot welded joint of at least two steel sheets. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05≦C≦0.21%, 4.0≦Mn≦7.0%, 0.5≦Al≦3.5%, Si≦2.0%, Ti≦0.2%, V≦0.2%, Nb≦0.2%, P≦0.025%, B≦0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 μmand containing more than the steel nominal phosphorus content. 121-. (canceled)22. A spot welded joint for connecting at least two steel sheets , comprising:a spot welded joint; andat least one sheet connected to the spot welded joint; [{'br': None, '0.05≦C≦0.21%;'}, {'br': None, '4.0≦Mn≦7.0%;'}, {'br': None, '0.5≦Al≦3.5%;'}, {'br': None, 'Si≦2.0%;'}, {'br': None, 'Ti≦0.2%;'}, {'br': None, 'V≦0.2%;'}, {'br': None, 'Nb≦0.2%;'}, {'br': None, 'P≦0.025%;'}, {'br': None, 'B≦0.0035%; and'}, {'br': None, 'S≦0.004%;'}, 'a balance of the composition being iron and unavoidable impurities resulting from the smelting;, 'the at least one sheet made of an aluminium alloyed steel comprising, by weight percent a yield strength above or equal to 600 MPa;', 'an ultimate tensile strength above or equal to 1000 MPa; and', 'uniform elongation above or equal to 15%;, 'the at least one aluminium alloyed steel sheet havinga microstructure of the at least one aluminium alloyed steel sheet including from 20% to 50% of austenite, from 40% to 80% of annealed ferrite and less than 25% of martensite; and a molten zone microstructure including more than 0.5% of Al; and', {'sup': '2', 'a surface fraction of segregated areas lower than 1%, the segregated areas being zones larger than 20 μmand including an amount of phosphorous greater than a aluminium alloyed steel nominal phosphorus ...

GRAIN-ORIENTED ELECTRICAL STEEL SHEET AND MANUFACTURING METHOD THEREOF

A silicon steel sheet () containing Si is cold-rolled. Next, a decarburization annealing () of the silicon steel sheet () is performed so as to cause a primary recrystallization. Next, the silicon steel sheet () is coiled so as to obtain a steel sheet coil (). Next, an annealing () of the steel sheet coil () is performed through batch processing so as to cause a secondary recrystallization. Next, the steel sheet coil () is uncoiled and flattened. Between the cold-rolling and the obtaining the steel sheet coil (), a laser beam is irradiated a plurality of times at predetermined intervals on a surface of the silicon steel sheet () from one end to the other end of the silicon steel sheet () along a sheet width direction (). When the secondary recrystallization is caused, grain boundaries passing from a front surface to a rear surface of the silicon steel sheet () along paths of the laser beams are generated. 1. A manufacturing method of a grain-oriented electrical steel sheet , comprising:cold-rolling a silicon steel sheet containing Si;next, performing a decarburization annealing of the silicon steel sheet so as to cause a primary recrystallization;next, coiling the silicon steel sheet so as to obtain a steel sheet coil;next, performing an annealing of the steel sheet coil through batch processing so as to cause a secondary recrystallization; andnext, uncoiling and flattening the steel sheet coil, whereinthe manufacturing method further comprising, between the cold-rolling the silicon steel sheet containing Si and the coiling the silicon steel sheet so as to obtain the steel sheet coil, irradiating a laser beam a plurality of times at a predetermined interval in a rolling direction on a surface of the silicon steel sheet from one end to the other end of the silicon steel sheet along a sheet width direction, andwhile the secondary recrystallization is caused, grain boundaries passing from a front surface to a rear surface of the silicon steel sheet are generated along ...

AUTOMOBILE PART AND METHOD FOR MANUFACTURING AUTOMOBILE PART

[Object] There are provided automobile parts and a method for manufacturing the automobile parts. The automobile parts have an excellent corrosion resistance after coated with a electrodeposition paint with smaller thickness, improve formability and productivity in hot pressing, and also improve chemical conversion treatability after hot press-forming. 1. A method for manufacturing an automobile part , the method comprising:using an Al plated steel sheet including a coating containing ZnO on a surface of the Al plated steel sheet;using a hot pressing method;{'sup': 2', '2, 'causing an Al plating layer having an average primary crystal diameter of 4 μm or more and 40 μm or less to have an amount of plating of 30 g/mor more and 110 g/mor less for one surface;'}{'sup': 2', '2, 'causing a ZnO amount of the coating containing ZnO to be 0.3 g/mor more and 3 g/mor less in metallic Zn equivalent for one surface;'}causing a rate of temperature increase during a heating process in hot pressing to be 12° C./second or more;causing a reaching steel sheet temperature to be 870° C. or more and 1100° C. or less; andcausing a electrodeposition paint film to have thickness of 6 μm or more and less than 15 μm.2. The method for manufacturing an automobile part according to claim 1 , wherein an amount of the Al plating layer is 50 g/mor more and 80 g/mor less for one surface.3. A method for manufacturing a high-strength automobile part claim 1 , the method comprising:using an Al plated steel sheet including a coating containing ZnO on a surface of the Al plated steel sheet;using a hot pressing method;{'sup': 2', '2, 'causing an Al plating layer having an average primary crystal diameter of 4 μm or more and 40 μm or less to have an amount of plating of 30 g/mor more and less than 60 g/mfor one surface;'}{'sup': 2', '2, 'causing a ZnO amount of the coating containing ZnO to be 0.3 g/mor more and 3 g/mor less as metallic Zn for one surface;'}causing a rate of temperature increase during a ...

GALVANNEALED STEEL SHEET AND METHOD FOR PRODUCING THE SAME (AS AMENDED)

A galvannealed steel sheet having a galvanized layer on a surface thereof is provided, having a composition which contains C: 0.10% to 0.35%, Si: 0.3% to 3.0%, Mn: 0.5% to 3.0%, P: 0.001% to 0.10%, Al: 0.01% to 3.00%, and S: 0.200% or less on a mass basis, the remainder being Fe and incidental impurities. The steel sheet has a SiC/SiOratio of more than 0.20, the SiC/SiOratio being a ratio of SiC amount to SiOamount at a depth of 1 μm or less in the steel sheet from an interface between the steel sheet and the galvanized layer, and Fe in the galvanized layer constitutes 8% to 13% by mass. 1. A galvannealed steel sheet having a galvanized layer on a surface thereof , said steel sheet having a composition comprising on a mass basis: C: 0.10% to 0.35% , Si: 0.3% to 3.0% , Mn: 0.5% to 3.0% , P: 0.001% to 0.10% , Al: 0.01% to 3.00% , and S: 0.200% or less , a remainder being Fe and incidental impurities ,{'sub': 2', '2', '2, 'wherein the steel sheet has a SiC/SiOratio of more than 0.20, the SiC/SiOratio being a ratio of SiC amount to SiOamount at a depth of 1 μm or less in the steel sheet from an interface between the steel sheet and the galvanized layer, and'}Fe in the galvanized layer constitutes 8% to 13% by mass.2. The galvannealed steel sheet according to claim 1 , wherein a retained austenite phase constitutes 0.2% or more by area of the steel sheet at a depth of 1 μm or less in the steel sheet from the interface between the steel sheet and the galvanized layer.3. The galvannealed steel sheet according to claim 1 , the composition further comprising one or two selected from Mo: 0.01% to 1.00% and Cr: 0.01% to 1.00% on a mass basis.4. The galvannealed steel sheet according to claim 1 , the composition further comprising one or two or more selected from Nb: 0.005% to 0.20% claim 1 , Ti: 0.005% to 0.20% claim 1 , Cu: 0.01% to 0.50% claim 1 , Ni: 0.01% to 1.00% claim 1 , and B: 0.0005% to 0.010% on a mass basis.5. A method for producing a galvannealed steel sheet claim ...

Part with very High Mechanical Properties from a Rolled Coated Sheet

The present invention provides a steel part. The steel part includes a steel precoated with a zinc-based alloy including, the contents being expressed by weight, from 0.5 to 2.5% aluminum and, optionally, one or more elements chosen from the group of: Pb≦0.003%; Sb≦0.003%; Bi≦0.003%; 0.002%.≦Si≦0.070%; La<0.05%; and Ce<0.05%. A balance of the precoat includes zinc and inevitable impurities. The steel part also includes a compound formed by at least one heat treatment for alloying between the steel and the precoat. The compound includes over more than 90% of its thickness, at least one Fe/Zn-based phase, the iron weight content of which is equal to 65% or higher and the Fe/Zn ratio of which is between 1.9 and 4. A structural or safety part is also provided. 2. The steel part as recited in claim 1 , wherein aluminum content of the precoat is greater than 0.7% but not more than 0.8% by weight.3. The steel part as recited in claim 1 , wherein the aluminum content of the precoat is greater than 0.8% but not more than 2.5% by weight.4. The steel part as recited in claim 1 , wherein the aluminum content of the precoat is not less than 0.5% and not more than 0.7% by weight.5. The steel part as recited in claim 1 , wherein a composition of the steel comprises claim 1 , the contents being expressed by weight:0.15%≦C≦0.5%;0.5%≦Mn≦3%;0.1%≦Si≦0.5%;0.01%≦Cr≦1%;Ti≦0.2%;Al≦0.1%;S≦0.05%;P≦0.1%; and0.0005%≦B≦0.010%,a balance of the composition including iron and inevitable impurities resulting from the smelting.6. The steel part as claimed in claim 5 , wherein the composition of the steel comprises claim 5 , the contents being expressed by weight:0.15%≦C≦0.25%;0.8%≦Mn≦1.5%;0.1%≦Si≦0.35%;0.01%≦Cr≦0.3%;Ti≦0.1%;Al≦0.1%;S≦0.05%;P≦0.1%; and0.002%≦B≦0.005%;a balance of the composition including iron and inevitable impurities resulting from the smelting.7. A structural or safety part for a terrestrial motor vehicle comprising:{'claim-ref': {'@idref': 'CLM-00001', 'claim 1'}, 'a steel part ...

Method for Producing a Flat Steel Product Provided with a Metal Protective Layer by Way of Hot Dip Coating

Optimal wetting and adhesion of the hot-dip coating by way of pre-oxidation in a DFF pre-heating furnace and humidification of the annealing atmosphere in a holding zone is achieved in a hot dip galvanised flat steel product.

HOT-ROLLED STEEL SHEET FOR TAILORED ROLLED BLANK AND TAILORED ROLLED BLANK

A hot-rolled steel sheet has a chemical composition that contains, in mass %, C, Si, Mn, P, S, Al, N and Ti, and that satisfies Formula (1); and a microstructure containing bainite and ferrite. In the interior of the steel sheet an average value of pole densities of an orientation group {100}<011> to {223}<110> is 4 or less, and a pole density of a {332}<113> crystal orientation is 4.8 or less. In an outer layer of the steel sheet, a pole density of a {110}<001> crystal orientation is 2.5 or more. Furthermore, among Ti carbo-nitrides in the steel sheet, the number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is 1.0×10per cmor less, and a bake hardening amount is 15 MPa or more. 116-. (canceled)17. A hot-rolled steel sheet for a tailored rolled blank comprising:a chemical composition consisting of, in mass %,C: 0.03 to 0.1%,Si: 1.5% or less,Mn: 1.0 to 2.5%,P: 0.1% or less,S: 0.02% or less,Al: 0.01 to 1.2%,N: 0.01% or less,Ti: 0.015 to 0.15%,Nb: 0 to 0.1%,Cu: 0 to 1%,Ni: 0 to 1%,Mo: 0 to 0.2%,V: 0 to 0.2%,Cr: 0 to 1%,W: 0 to 0.5%,Mg: 0 to 0.005%,Ca: 0 to 0.005%,rare earth metal: 0 to 0.1%,B: 0 to 0.005%, andone or more types of element selected from a group consisting of Zr, Sn, Co and Zn in a total amount of 0 to 0.05%, with the balance being Fe and impurities, and satisfying Formula (1); anda microstructure containing, in terms of area ratio, 20% or more of bainite, with 50% or more in terms of area ratio of the balance being ferrite;wherein:at a depth position that is equivalent to one-half of a sheet thickness from a surface of the hot-rolled steel sheet, an average value of pole densities of an orientation group {100}<011> to {223}<110> comprising crystal orientations {100}<011>, {116}<110>, {114}<110>, {113}<110>, {112}<110>, {335}<110> and {223}<110> is four or less and a pole density of a {332}<113> crystal orientation is 4.8 or less;at a depth position that is equivalent to one-eighth of the sheet thickness from the surface of ...

Steel foil for power storage device container, power storage device container, power storage device, and manufacturing method of steel foil for power storage device container

A steel foil for a power storage device container includes a rolled steel foil, a nickel layer formed on a surface of the rolled steel foil, and a chromium-based surface treatment layer formed on a surface of the nickel layer. The nickel layer includes an upper layer portion which is in contact with the chromium-based surface treatment layer and contains Ni of 90 mass % or more among metal elements, and a lower layer portion which is in contact with the rolled steel foil and contains Ni of less than 90 mass % among the metal elements and Fe. <111> polar density in a reverse pole figure of the nickel layer in a rolling direction is 3.0 to 6.0. The nickel layer has a sub-boundary which is a boundary between two crystals having a relative orientation difference of 2° to 5°, and a large angle boundary which is a boundary between two crystals having the relative orientation difference of equal to or more than 15°. The average value of a ratio L 5 /L 15 between a boundary length L 5 which is the length of the sub-boundary, and a boundary length L 15 which is the length of the large angle boundary, is equal to or more than 1.0.

HIGH-STRENGTH COLD-ROLLED STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

A high-strength cold-rolled steel sheet has a composition and a microstructure. The microstructure comprises: ferrite having an average grain size of 5 um or less and a volume fraction of 3% to 20%, retained austenite having a volume fraction of 5% to 20%, and martensite having a volume fraction of 5% to 20%, the remainder being bainite and/or tempered martensite. The total number of retained austenite with a grain size of 2 μm or less, martensite with a grain size of 2 μm or less, or a mixed phase thereof is 150 or more per 2,000 μmof a thickness cross section parallel to the rolling direction of the steel sheet. 16-. (canceled)8. The high-strength cold-rolled steel sheet according to claim 7 , wherein the composition further contains at least one selected from the group consisting of 0.10% or less V claim 7 , 0.10% or less Nb claim 7 , and 0.10% or less Ti on a mass basis.9. The high-strength cold-rolled steel sheet according to claim 7 , wherein the composition further contains 0.0050% or less B on a mass basis.10. The high-strength cold-rolled steel sheet according to claim 7 , wherein the composition further contains at least one selected from the group consisting of 0.50% or less Cr claim 7 , 0.50% or less Mo claim 7 , 0.50% or less Cu claim 7 , and 0.50% or less Ni on a mass basis.11. The high-strength cold-rolled steel sheet according to claim 7 , wherein the composition further contains at least one selected from the group consisting of 0.0050% or less Ca and 0.0050% or less of a REM on a mass basis. This disclosure relates to high-strength cold-rolled steel sheets and methods of manufacturing the same and particularly relates to a high-strength cold-rolled steel sheet suitable for use in members for structural parts of automobiles and the like and a method of manufacturing the high-strength cold-rolled steel sheet.In recent years, COemissions have been strictly regulated due to growing environmental issues. In the automotive field, improvements in fuel ...

HIGH-YIELD-RATIO, HIGH-STRENGTH COLD ROLLED STEEL SHEET AND PRODUCTION METHOD THEREFOR

A steel sheet includes a microstructure containing a volume fraction of 20% to 55% of ferrite having an average grain size of 7 μm or less, a volume fraction of 5% to 15% of retained austenite, a volume fraction of 0.5% to 7% of martensite having an average grain size of 4 μm or less, and a structure composed of bainite and/or tempered martensite and having an average grain size of 6 μm or less, and a difference in nano-hardness between ferrite and the structure composed of bainite and/or tempered martensite being 3.5 GPa or less and a difference in nano-hardness between the structure composed of bainite and/or tempered martensite and martensite being 2.5 GPa or less. 15.-. (canceled)6. A high-yield-ratio , high-strength cold rolled steel sheet , comprising a composition and a microstructure ,the composition comprising, in terms of percent by mass, C: 0.05% to 0.15%, Si: 0.6% to 2.5%, Mn: 2.2% to 3.5%, P: 0.08% or less, S: 0.010% or less, Al: 0.01% to 0.08%, N: 0.010% or less, Ti: 0.002% to 0.05%, B: 0.0002% to 0.0050%, and the balance being Fe and unavoidable impurities,the microstructure comprising a volume fraction of 20% to 55% of ferrite having an average grain size of 7 μm or less, a volume fraction of 5% to 15% of retained austenite, a volume fraction of 0.5% to 7% of martensite having an average grain size of 4 μm or less, and a structure composed of composed of bainite and/or tempered martensite and having an average grain size of 6 μm or less, anda difference in nano-hardness between the ferrite and the structure composed of composed of bainite and/or tempered martensite being 3.5 GPa or less, anda difference in nano-hardness between the structure composed of composed of bainite and/or tempered martensite and the martensite being 2.5 GPa or less.7. The steel sheet according to claim 6 , wherein the composition further comprises claim 6 , in terms of percent by mass claim 6 , at least one selected from V: 0.10% or less and Nb: 10% or less.8. The steel sheet ...

HIGH-STRENGTH COLD-ROLLED STEEL SHEET, HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET, AND HIGH-STRENGTH HOT-DIP GALVANNEALED STEEL SHEET HAVING EXCELLENT DUCTILITY, STRETCH-FLANGEABILITY, AND WELDABILITY

Provided is a high-strength cold-rolled steel sheet having excellent ductility and stretch-flangeability as well as weldability in a range in which a tensile strength is 980 MPa or higher and a 0.2% yield strength is 700 MPa or higher. In the high-strength cold-rolled steel sheet of the present invention, the chemical composition is adjusted as appropriate, and the area ratio of below-mentioned metal structures at a position of ¼ sheet thickness in the steel sheet satisfies following requirements: tempered martensite: 30 area % or more, bainite: 15 area % to 70 area %, total of tempered martensite and bainite: 90 area % or more, ferrite: 0 area % to 5 area %, and retained austenite: 0 area % to 4 area %. The high-strength cold-rolled steel sheet has excellent ductility, stretch-flangeability, and weldability, and has a tensile strength of 980 MPa or higher and a 0.2% yield strength of 700 MPa or higher. 1: A high-strength cold-rolled steel sheet with a tensile strength of 980 MPa or higher and a 0.2% yield strength of 700 MPa or higher ,the high-strength cold-rolled steel sheet comprising: in percent by mass,C: 0.07% to 0.15%,Si: 1.1% to 1.6%,Mn: 2.0% to 2.8%,P: more than 0% to 0.015%,S: more than 0% to 0.005%,Al: 0.015% to 0.06%,Ti: 0.010% to 0.03%, andB: 0.0010% to 0.004%,with the balance being iron and inevitable impurities,whereinan area ratio of following metal structures at a position of ¼ sheet thickness in the steel sheet satisfies following requirements:tempered martensite: 30 area % or more,bainite: 15 area % to 70 area %,total of tempered martensite and bainite: 90 area % or more,ferrite: 0 area % to 5 area %, andretained austenite: 0 area % to 4 area %.2: The high-strength cold-rolled steel sheet according to claim 1 , further comprising one or more selected from the group consisting of: in percent by mass claim 1 ,Cu: more than 0% to 0.3%,Ni: more than 0% to 0.3%,Cr: more than 0% to 0.3%,Mo: more than 0% to 0.3%,V: more than 0% to 0.3%, andNb: more than ...

Hot Dip Galvanized and Galvannealed Steel Sheet Having Excellent Elongation Properties, And Method For Manufacturing The Same

There is provided a hot-dip galvanized steel sheet and a hot-dip galvannealed steel sheet, which have excellent elongation properties, and methods for manufacturing the hot-dip galvanized steel sheet and the hot-dip galvannealed steel sheet. The present disclosure relates to a hot-dip galvanized steel sheet in which a hot-dip galvanized layer is formed on a surface of a base steel sheet, the hot-dip galvanized steel sheet having excellent elongation properties and being characterized by the composition and the microstructure thereof. 1. A hot-dip galvanized steel sheet in which a hot-dip galvanized layer is formed on a surface of a base steel sheet , the hot-dip galvanized steel sheet having excellent elongation properties , whereinthe base steel sheet:contains 0.02-0.08% of carbon (C), 1.3-2.1% of manganese (Mn), 0.3% or less of silicon (Si) (excluding 0%), 1.0% or less of chromium (Cr) (excluding 0%), 0.1% or less of phosphorous (P) (excluding 0%), 0.01% or less of sulfur (S) (excluding 0%), 0.01% or less of nitrogen (N) (excluding 0%), 0.02-0.06% of aluminum (sol. Al), 0.2% or less of molybdenum (Mo) (excluding 0%), 0.003% or less of boron (B) (excluding 0%), and a remainder of Fe and other inevitable impurities, in wt %;has a microstructure including 90% or more of ferrite, and a remainder of martensite and 3% or less of bainite, as defined by Equation 1;contains a percentage of martensite (M %) having an average particle diameter of 5 μm or less occupying space in ferrite grain boundaries (including grain boundary triple points) of 90% or higher, as defined by Equation 2; and {'br': None, 'i': B', 'BA', 'MA+BA, '(%)={/()}×100\u2003\u2003[Equation 1]'}, 'at ¼t based on the thickness (t) of the sheet, the ratio of a C concentration (a) in the ferrite phase to a C concentration (b) in the martensite phase, i.e., (a)/(b), is 0.7 or less, and the ratio of an Mn concentration (c) in the ferrite phase to an Mn concentration (d) in the martensite phase, i.e., (c)/(d), ...

Micro-alloyed high-strength multi-phase steel containing silicon and having a minimum tensile strength of 750 mpa and improved properties and method for producing a strip from said steel

A high-strength multi-phase steel having minimum tensile strengths of 750 MPa and preferably having a dual-phase microstructure for a cold- or hot-rolled steel strip, in particular for lightweight vehicle construction is disclosed. The high-strength multi-phase steel has improved forming properties and a ratio of yield point to tensile strength of at most 73%. The high-strength multi-phase steel includes in mass %: C≧0.075 to ≦0.105; Si≧0.600 to ≦0.800; Mn≧1.000 to ≦0.700; Cr≧0.100 to ≦0.480; Al≧0.010 to ≦0.060; N 0.0020≦0.0120; S≦0.0030; Nb≧0.005 to ≦0.050; Ti≧0.0050 to ≦0.050; B≧0.0005 to ≦0.0040; Mo≦0.200; Cu≦0.040%; Ni≦0.040% the remainder iron, including typical elements accompanying steel that are not mentioned above, which represent contamination resulting from smelting.

COLD-ROLLED STEEL SHEET AND PLATED STEEL SHEET

A cold-rolled steel sheet includes, by mass %: C: 0.020% or more and 0.080% or less; Si: 0.20% or more and 1.00% or less; Mn: 0.80% or more and 2.30% or less; and Al: 0.010% or more and 0.100% or less; and further includes: one or more of Nb and Ti which satisfy a requirement of 0.005%≤Nb+Ti<0.030%, in which a structure consists of, ferrite, bainite, and other phases, an area ratio of the ferrite is 80% or more and less than 95%, an area ratio of a non-recrystallization ferrite in the ferrite is 1% or more and less than 10%, an area ratio of the bainite is 5% or more and 20% or less, a total amount of the other phases is less than 8%, an equivalent circle diameter of a carbonitride including one or both of Nb and Ti is 1 nm or more and 10 nm or less, and a tensile strength is 590 MPa or more. 1. A cold-rolled steel sheet comprising , by mass %:C: 0.020% or more and 0.080% or less;Si: 0.20% or more and 1.00% or less;Mn: 0.80% or more and 2.30% or less;P: 0.0050% or more and 0.1500% or less;S: 0.0020% or more and 0.0150% or less;Al: 0.010% or more and 0.100% or less;N: 0.0010% or more and 0.0100% or less; and further comprising:one or more of Nb and Ti which satisfy a requirement of 0.005%≤Nb+Ti<0.030%; anda remainder including Fe and unavoidable impurities,wherein a structure consists of, a ferrite, a bainite, and an other phase,the other phase includes one or more of a pearlite, a residual austenite, and a martensite,an area ratio of the ferrite is 80% or more and less than 95%,an area ratio of a non-recrystallization ferrite in the ferrite is 1% or more and less than 10%,an area ratio of the bainite is 5% to 20%,a total amount of the other phase is less than 8%,an equivalent circle diameter of a carbonitride including one or both of Nb and Ti is 1 nm or more and 10 nm or less, anda tensile strength is 590 MPa or more.2. The cold-rolled steel sheet according to claim 1 , further comprising one or more of claim 1 , by mass %:Mo: 0.005% or more and 1.000% or less;W: 0 ...

HIGH-STRENGTH COLD-ROLLED STEEL SHEET, HIGH-STRENGTH HOT-DIP GALVANIZED STEEL SHEET, AND HIGH-STRENGTH HOT-DIP GALVANNEALED STEEL SHEET HAVING EXCELLENT DUCTILITY, STRETCH-FLANGEABILITY, AND WELDABILITY

Provided is a high-strength cold-rolled steel sheet having excellent ductility and stretch-flangeability as well as weldability in a range in which a tensile strength is 980 MPa or higher and a 0.2% yield strength is less than 700 MPa (preferably 500 MPa or higher). In the high-strength cold-rolled steel sheet of the present invention, the chemical composition is adjusted as appropriate, and the area ratio of below-mentioned metal structures at a position of ¼ sheet thickness in the steel sheet satisfies following requirements: tempered martensite: 10 area % to less than 30 area %, bainite: more than 70 area %, total of tempered martensite and bainite: 90 area % or more, ferrite: 0 area % to 5 area %, and retained austenite: 0 area % to 4 area %. The high-strength cold-rolled steel sheet has excellent ductility, stretch-flangeability, and weldability, and has a tensile strength of 980 MPa or higher and a 0.2% yield strength of less than 700 MPa. 1. A high-strength cold-rolled steel sheet comprising: in percent by mass ,C: 0.07% to 0.15%,Si: 1.1% to 1.6%,Mn: 2.0% to 2.8%,P: more than 0% to 0.015%,S: more than 0% to 0.005%,Al: 0.015% to 0.06%,Ti: 0.010% to 0.03%,B: 0.0010% to 0.004%, andwherein an area ratio of following metal structures at a position of ¼ sheet thickness in the steel sheet satisfies following requirements:tempered martensite: 10 area % to less than 30 area %,bainite: more than 70 area %,total of tempered martensite and bainite: 90 area % or more,ferrite: 0 area % to 5 area %, andretained austenite: 0 area % to 4 area %.2. The steel sheet according to claim 1 , further comprising: Cu: more than 0% to 0.3%,', 'Ni: more than 0% to 0.3%,', 'Cr: more than 0% to 0.3%,', 'Mo: more than 0% to 0.3%,', 'V: more than 0% to 0.3%, and', 'Nb: more than 0% to 0.03%., 'one or more selected from the group consisting of: in percent by mass,'}3. The steel sheet according to claim 1 , further comprising: in percent by mass claim 1 , Ca: more than 0% to 0.005%.4. The ...

FERRITIC STAINLESS STEEL AND METHOD FOR PRODUCING SAME

Provided is a ferritic stainless steel that has excellent corrosion resistance and displays good brazing properties when brazing is carried out at high temperature using a Ni-containing brazing metal. These effects are obtained as a result of the steel having a chemical composition containing, in mass %: 0.003%-0.020% of C; 0.05%-1.00% of Si; 0.10%-0.50% of Mn, 0.04% or less of P; 0.01% or less of S; 16.0%-25.0% of Cr; 0.05%-0.60% of Ni; 0.25%-0.45% of Nb; 0.005%-0.15% of Al; 0.005%-0.030% of N; and at least one selected from 0.50%-2.50% of Mo and 0.05%-0.80% of Cu, the balance being Fe and incidental impurities, and as a result of a nitrogen-enriched layer being created that has a nitrogen concentration peak value of 0.03 to 0.30 mass % at a depth of within 0.05 μm of a surface of the steel. 1. A ferritic stainless steel comprisinga chemical composition containing, in mass %:0.003% to 0.020% of C;0.05% to 1.00% of Si;0.10% to 0.50% of Mn;0.04% or less of P;0.01% or less of S;16.0% to 25.0% of Cr;0.05% to 0.60% of Ni;0.25% to 0.45% of Nb;0.005% to 0.15% of Al;0.005% to 0.030% of N; andat least one selected from 0.50% to 2.50% of Mo and 0.05% to 0.80% of Cu,the balance being Fe and incidental impurities, whereina nitrogen-enriched layer is present that has a nitrogen concentration peak value of 0.03 mass % to 0.30 mass % at a depth of within 0.05 μm of a surface of the steel.2. The ferritic stainless steel of claim 1 , whereinthe chemical composition further contains, in mass %, one or more of:0.005% to 0.10% of Ti;0.01% to 0.20% of V;0.0003% to 0.0030% of Ca; and0.0003% to 0.0030% of B.3. A method for producing the ferritic stainless steel of claim 1 , the method comprising:{'claim-ref': {'@idref': 'CLM-00001', 'claim 1'}, 'hot rolling a slab having the chemical composition of to form a hot-rolled sheet;'}performing hot-rolled sheet annealing on the hot-rolled sheet according to need; andperforming a combination of cold rolling and annealing on the hot-rolled sheet ...

Hot Rolled Steel Sheet and Associated Manufacturing Method

The present invention provides a hot rolled steel sheet. The hot rolled steel sheet has a yield stress greater than 680 MPa and less than or equal to 840 MPa, at least in a direction transverse to a rolling direction, strength between 780 MPa and 950 MPa, elongation at failure greater than 10% and hole-expansion ratio (Ac) greater than or equal to 45%. The chemical composition includes, with the contents expressed by weight: 21: A hot rolled steel sheet comprising:a thickness between 1.5 and 4.5 millimeters;a yield stress at least greater than 680 MPa in a direction transverse to a rolling direction and less than or equal to 840 MPa,a strength between 780 MPa and 950 MPa;elongation at failure greater than 10%;a hole expansion ratio (Ac) greater than or equal to 45%, 0.04%≦C≦0.08%;', '1.2%≦Mn≦1.9%;', '0.1%≦Si≦0.3%;', '0.07%≦Ti≦0.125%;', '0.05%≦Mo≦0.35%;', '0.15%≦Cr≦0.6% when 0.05%≦Mo≦0.11%; or', '0.10%≦Cr≦0.6% when 0.11%≦Mo≦0.35%;', 'Nb≦0.045%;', '0.005%≦Al≦0.1%;', '0.002%≦N≦0.01%;', 'S≦0.004%; and', 'P≦0.020%;', 'a remainder of the chemical composition including iron and unavoidable impurities resulting from processing, and, 'a chemical composition comprising, expressed by weight granular bainite, an area percentage of which is greater than 70%, and', 'ferrite, an area percentage of which is less than 20%,', 'a remainder, if any, consisting of lower bainite, martensite and residual austenite, a sum of the martensite and residual austenite being less than 5%., 'a microstructure including22: The rolled steel sheet according to claim 21 , wherein the chemical composition further includes 0.001%≦V≦0.2%.24: The steel sheet according to claim 21 , wherein the chemical composition includes claim 21 , expressed by weight:0.27%≦Cr≦0.52% when 0.05%≦Mo≦0.11%, or0.10%≦Cr≦0.52% when 0.11%≦Mo≦0.25%25: The steel sheet according claim 21 , wherein the chemical composition includes claim 21 , expressed by weight:0.05%≦Mo≦0.18%, and in that:0.16%≦Cr≦0.55% when 0.05%≦Mo≦0.11%, or0.10 ...

Cold-rolled steel sheet and method for producing same

A cold-rolled steel sheet satisfies that an average pole density of an orientation group of {100}<011> to {223}<110> is 1.0 to 5.0, a pole density of a crystal orientation {332}<113> is 1.0 to 4.0, a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50, and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50. Moreover, the cold-rolled steel sheet includes, as a metallographic structure, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.

METHOD FOR FABRICATING STEEL SHEET FOR PRESS HARDENING, AND PARTS OBTAINED BY THIS METHOD

The present invention provides fabrication methods for cold rolled, precoated and press hardened steel sheets, for which the chemical composition includes, with contents expressed by weight, 0.24%≤C≤0.38%, 0.40%≤Mn≤3%, 0.10%≤Si≤0.70%, 0.015%≤Al≤0.070%, 0%≤Cr≤2%, 0.25%≤Ni≤2%, 0.015%≤Ti≤0.10%, 0%≤Nb≤0.060%, 0.0005%≤B≤0.0040%, 0.003%≤N≤0.010%, 0.0001%≤S≤0.005%, 0.0001%≤P≤0.025%, it being understood that the titanium and nitrogen content satisfy: Ti/N>3.42, and that the carbon, manganese, chromium and silicon content satisfy: 2.6C+Mn/5.3+Cr/13+Si/15≥1.1%, with the chemical composition optionally including one or more of the following elements: 0.05%≤Mo≤0.65%, 0.001%≤W≤0.30%, 0.0005%≤Ca≤0.005%, with the remainder made up of iron and inevitable impurities coming from preparation. 3. The fabrication method as recited in wherein the performing step is with the aluminum or aluminum-based alloy; and further comprising performing a thermal pretreatment of the precoated sheet at a temperature θ1 between 620° C. and 680° C. for a holding time t1 between 6 and 15 hours claim 2 , such that the pre-coating no longer contains free aluminum of phase τof type FeSiAl claim 2 , and τof type FeSiAl claim 2 , and such that an austenitic transformation does not occur in the steel substrate claim 2 , the pretreatment being done in a furnace under hydrogen and nitrogen atmosphere.5. The fabrication method as recited in wherein the steps are performed successively.6. The fabrication method as recited in further comprising the step of deforming the blank by cold stamping after the step of cutting the sheet.7. The fabrication method as recited in wherein the chemical composition includes at least one of the following elements claim 4 , by weight:0.05%≤Mo≤0.65%;0.001%≤W≤0.30%; and0.0005%≤Ca≤0.005%.8. The fabrication method as recited in wherein the chemical composition includes claim 4 , by weight:0.32%≤C≤0.36%;0.40%≤Mn≤0.80%; and0.05%≤Cr≤1.20%.9. The fabrication method as recited in wherein the ...

Steel sheet for containers, and method for producing steel sheet for containers

This steel sheet for containers includes a steel sheet, a Sn coated layer that is formed on at least one surface of the steel sheet, and a chemical treatment layer that is formed on the Sn coated layer. The Sn coated layer contains 300 mg/m 2 to 5,600 mg/m 2 of Sn in terms of an amount of metal Sn, and the chemical treatment layer contains 5 mg/m 2 to 30 mg/m 2 of a Zr compound in terms of an amount of metal Zr, an average roughness Ra of an outermost surface of the chemical treatment layer obtained with a scanning probe microscope is 10 nm to 100 nm. A variation amount in a yellowness index measured at one measurement point on the outermost surface of the chemical treatment layer is defined as ΔYI represented by Equation (1), an average of absolute values of the ΔYI obtained at a plurality of the measurement points included in a unit area of the outermost surface is 5.0 or less. Δ YI=YI−YI 0   (1) where YI: the yellowness index measured after the steel sheet for containers is subjected to a retort treatment at a temperature of 130° C. for 5 hours, YI 0 : the yellowness index measured before the retort treatment

Flat Steel Product, Method for Production of a Flat Steel Product and Method for Production of a Component

A flat steel product which is provided for forming into a component by hot pressing and which has a base layer of steel on which is applied a Zn or Zn alloy metallic protective coating for protecting against corrosion. On at least one of the free surfaces of the flat steel product, a separate cover layer is applied which contains an oxide, nitride, sulphide, carbide, hydrate or phosphate compound of a base metal. In addition, a method which allows the production of such a flat steel product, and a method which allows the production of a component from such a flat steel product. 1. A hot-press formed component comprising a steel product comprising a base layer comprising steel on which is applied a metallic protective coating for protecting against corrosion comprising a Zn or a Zn alloy , wherein on at least one of the free surfaces of the flat steel product a separate cover layer is applied which comprises an oxide , nitride , sulphide , carbide , hydrate , or phosphate compound of a base metal.2. The hot-press formed component according to claim 1 , wherein the base metal of the compound belongs to the group of alkaline earth metals.3. The hot-press formed component according to claim 1 , wherein the base metal of the compound belongs to the group of alkali metals.4. The hot-press formed component according to claim 1 , wherein the base metal of the compound belongs to the group of semimetals.5. The hot-press formed component according to claim 1 , wherein the base metal belongs to the group of transition metals.6. The hot-press formed component according to claim 1 , wherein the base metal of the compound belongs to the group consisting of Na claim 1 , K claim 1 , Mg claim 1 , Ca claim 1 , B claim 1 , Al claim 1 , Si claim 1 , Sn claim 1 , Ti claim 1 , Cr claim 1 , Mn claim 1 , and Zn.7. The hot-press formed component according to claim 1 , wherein the compound present in the cover layer is present in the form of particles.8. The hot-press formed component ...

METHOD OF PRODUCING PRESS-HARDENED AND COATED STEEL PARTS AT A HIGH PRODUCTIVITY RATE

A part obtained by austenitization followed by hot stamping and hardening by holding in the stamping tool a sheet or blank is provided, including, a steel substrate, a precoating having at least one layer of aluminum or aluminum alloy, a microstructure of a steel substrate including martensite and/or bainite, a coating on at least one face of the steel substrate resulting from the interdiffusion between the steel substrate and the pre-coating and an oxide layer overlying the coating, an average content by weight of oxygen between 0 and 0.01 μm below a surface of the part being less than 25%, and the average percent by weight of oxygen between 0.1 and 0.2 μm below the surface being less than 10%. 1. A part obtained by austenitization followed by hot stamping and hardening by holding in the stamping tool a sheet or blank comprising:a steel substrate;a precoating having at least one layer of aluminum or aluminum alloy;a microstructure of a steel substrate including martensite and/or bainite;a coating on at least one face of the steel substrate resulting from the interdiffusion between the steel substrate and the pre-coating; andan oxide layer overlying the coating;an average content by weight of oxygen between 0 and 0.01 μm below a surface of the part being less than 25%, and the average percent by weight of oxygen between 0.1 and 0.2 μm below the surface being less than 10%.2. The part of claim 1 , wherein the average content by weight of oxygen between 0 and 0.01 μm below a surface of the part being 17.5% or less claim 1 , and the average percent by weight of oxygen between 0.1 and 0.2 μm below the surface being 4.8% or less.3. The part of claim 1 , wherein claim 1 , prior to austenitization claim 1 , a polymerized layer is provided on at least a part of the pre-coating claim 1 , the polymerized layer having a thickness from 2 μm to 30 μm and comprising a polymer that does not contain silicon claim 1 , a nitrogen content of less than 1% by weight and carbon pigments ...

METHOD FOR PRODUCING A ULTRA HIGH STRENGTH COATED OR NOT COATED STEEL SHEET AND OBTAINED SHEET

A method IS for producing a cold rolled steel sheet having a tensile strength ≥1470 MPa and a total elongation TE≥19%. The method includes the steps of annealing at an annealing temperature AT≥Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34%≤C≤0.40%, 1.50%≤Mn≤2.30%, 1.50≤Si≤2.40%, 0% Подробнее

Superlubricity coating containing carbon nanotubes

A method for producing a structure containing an array of MWCNTs on a metal substrate, comprising: (i) subjecting a metal substrate to a surface oxidation process at a first elevated temperature in an oxygen-containing atmosphere and under a first reduced pressure; (ii) subjecting the metal substrate to a surface reduction process at a second elevated temperature in a reducing atmosphere and under a second reduced pressure of at least 0.01 atm and less than 1 atm to result in reduction of the surface of said metal substrate, wherein the reducing atmosphere contains hydrogen gas; (iii) subjecting the metal substrate to a third reduced pressure of no more than 0.1 atm; and (iv) contacting the metal substrate, while at the third reduced pressure and under an inert or reducing atmosphere, with an organic substance at a third elevated temperature for suitable time to produce the MWCNTs on the metal substrate.

METHOD FOR MANUFACTURING HOT PRESS FORMED PART AND HOT PRESS FORMED PART

A method for manufacturing a hot press formed part, includes: preparing a hot press forming object comprising a single-ply portion and a two-ply portion; heating the hot press forming object to a temperature range from an Actransformation temperature of a base steel sheet of the first coated steel sheet to 1000° C.; press forming the hot press forming object to obtain a formed body, the press forming being started upon temperatures of the single-ply portion and of the two-ply portion being no higher than solidification points of Zn—Ni coating layers of the first and second coated steel sheets and no lower than an Artransformation temperature of the base steel sheet of the first coated steel sheet; and quenching the formed body to thereby obtain a hot press formed part, in which the hot press forming object has a thickness ratio from 1.4 to 5.0. 1. A method for manufacturing a hot press formed part , comprising:preparing a hot press forming object comprising a single-ply portion and a two-ply portion by welding first and second coated steel sheets together in partially overlapping relationship, each of the first and second coated steel sheets having a Zn—Ni coating layer formed on a surface thereof;{'sub': '3', 'heating the hot press forming object to a temperature range from an Actransformation temperature of a base steel sheet of the first coated steel sheet to 1000° C.;'}{'sub': '3', 'press forming the hot press forming object to obtain a formed body, the press forming being started upon temperatures of the single-ply portion and of the two-ply portion being no higher than solidification points of the Zn—Ni coating layers of the first and second coated steel sheets and no lower than an Artransformation temperature of the base steel sheet of the first coated steel sheet; and'}quenching the formed body, while squeezing the formed body by a tool of press forming and holding at its press bottom dead center, to thereby obtain a hot press formed part,{'sub': 2', '1', '1 ...

SPOT WELDED JOINT USING HIGH STRENGTH AND HIGH FORMING STEEL AND ITS PRODUCTION METHOD

A spot welded joint of at least two steel sheets is provided. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05≤C≤0.21%, 4.0≤Mn≤7.0%, 0.5≤Al≤3.5%, Si≤2.0%, Ti≤0.2%, V≤0.2%, Nb≤0.2%, P≤0.025%, B≤0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 μmand containing more than the steel nominal phosphorus content. 1. A spot welded joint for connecting at least two steel sheets , comprising:a spot welded joint, at least one aluminum alloyed steel sheet being connected to the spot welded joint, the at least one aluminum alloyed steel sheet including a nominal phosphorus content; a yield strength above or equal to 600 MPa;', 'an ultimate tensile strength above or equal to 1000 MPa; and', 'uniform elongation above or equal to 15%; and, 'the at least one aluminum alloyed steel sheet having a molten zone microstructure including more than 0.5% of Al; and', {'sup': '2', 'a surface fraction of segregated areas lower than 1%, the segregated areas being zones larger than 20 μmand including an amount of phosphorous greater than the nominal phosphorus content.'}], 'the spot-welded joint including2. The spot welded joint according to claim 1 , wherein the aluminum alloyed steel chemical composition has an aluminum content such that: 1.0≤Al≤3.0%.3. The spot welded joint according to claim 2 , wherein the aluminum alloyed steel chemical composition has an aluminum content such that: 1.0≤Al≤2.5%.4. The spot welded joint according to claim 2 , wherein the aluminum alloyed steel chemical composition has a silicon content such that: Si≤1.5%.5. The spot welded joint according to claim 4 , wherein the aluminum alloyed steel chemical composition ...