THREADED JOINT FOR PIPE OR BRANCH PIPE AND METHOD OF MANUFACTURING THREADED JOINT FOR PIPE OR BRANCH PIPE

2420 - 55097 6 [EA6/ 072

INVENTION PREREQUISITES

[0001] The present invention relates to threaded joint for pipe or branch pipe and production of threaded joint for pipe or branch pipe.

[0002] For drilling at oil or gas deposit, is used pipe oil field assortment. Proportion to the depth of well, much numeric steel pipes are connected for forming pipes oil field assortment. Joint of steel pipes is carried out by tightening of threaded compounds for tubes or branch pipes, made on end sections of steel pipes. Steel pipes tightened and loosened for checking or T. U ., and after checking, pipe tightened again and are used again.

[0003] Threaded joint for pipe or branch pipe includes nipple and coupling. Nipple has on external peripheral surface of front end section of steel pipe contact surface, including external threaded section and not having thread metal contact section. Coupling has on inner peripheral surface of front end section of steel pipe contact surface, including internal threaded section and not having thread metal contact section. Threaded sections and not having thread metal contact surface of nipple and coupling much is multiple are subjected to strong friction when tightening (fastening) and weakened (the unfastening) steel pipes. If data sections of not have sufficient resistance to friction, occurs scuff (not subject repair plunger) at repetition of tightening and attenuation. Therefore, is required sufficient stability to friction, namely, different score resistance for threaded joint for pipe or branch pipe.

[0004] In routine technology for improving resistance to the score is used composite consistent lubricant, called sealing tube lubricant, containing heavy metals. By means of application of composite grease on surface threaded joint for pipe or branch pipe may be improved score resistance threaded joint for pipe or branch pipe. Together with the, heavy metals, such as of Pb, ζη and xi, contained in composite consistent lubricant, may negatively effect on the environment. Along the said cause of is required development of threaded joint for pipe or branch pipe, not containing composite grease.

[0005] In publication patent application JapanesePatent the Application Publication No 2002 - 221288 (patent literature 1) and publication international application the International the Application Publication No w02009/072486 (patent literature 2) invention proposes threaded compounds for pipe or branch pipe, excellent resistance to to the score, even without composite grease.

[0006] On contact surfaces of nipple and coupling threaded joint for pipe or branch pipe, described in Patent literature 1, is formed porous layer ζη or porous layer alloy ζη, at least on one of threaded sections or not having thread metal contact sections threaded joint for pipe or branch pipe by covering covering up, and on layer is formed solid lubricating coating or thinned lubricating coating, not containing powders of heavy metals (for example, coating containing high main metallorganicheskuyu salt high main sulfonate or T. U ., as its main agent). Patent in

due to of or reducing gas permeability during repeating tightening/weakened at ridding from liquid lubricant, such as composite consistent lubricant, containing heavy-metal powders.

[0007] In the threaded joint for pipe or branch pipe described in Patent literature 2, contact surface of coupling includes, as the highest layer, solid lubricating coating with plastic or vyazkoplastichnymi rheological properties, and contact surface of nipple includes, as the highest layer, solid anticorrosive coating, containing hardened by ultraviolet radiation resin, as a basic component. In Patent literature 2 described is, that it is possible production of threaded joint for pipe or branch pipe, which suppresses occurrence of rust, without use of composite consistent lubricant, gives different score resistance and gas impermeability, has no nalipaemosti on surface and has different appearance and possibility for checking.

[0008] [Patent literature 1] publication patent application JapanesePatent the Application Publication No 2002 - 221288

[Patent literature 2] international publication the International application the Application Publication No w02009/072486

[0009] Evaluation of resistance to the score usually is, when steel pipes, to be tightening, they center with each other. Together with the, in actual tightening threaded joint for pipe or branch pipe steel pipes (or steel pipe and connecting coupling), to be tightening, may not be coaxial with each other. Said called misalignment of. When there is skewing, contact surfaces of nipple and coupling (threaded section and not having thread metal contact section) are subjected to strong friction, and also srezyvayushchemu voltage. This srezyvayushchee voltage considerably above, than in version where skewing does not occur. By particular cause of, when there is skewing, thread more is subjected to to the score. Therefore, functional possibility of suppression of scuff, even when skewing occurs, namely, capacity removing skewness, required for threaded joint for pipe or branch pipe.

[0010] The, described above, non-threaded metal contact section, includes metal sealing section and section bench. When tightening threaded joint for pipe or branch pipe sections benches nipple and coupling includes in contact with each other. Torque, caused in the given point, called torque at contact of benches. When tightening threaded joint for pipe or branch pipe, after achieving torque torque at contact of benches, lagging is additionally to completion of tightening. Said increases gas impermeability threaded joint for pipe or branch pipe. When lagging is additionally, metal, forming at least one nipple and coupling, begins to plastic deformation. Torque, caused in the given point, called torque on the limits of fluidity.

[UN] torque on completion of tightening (called torque tightening) is set so that pressure of at the joint for sufficient seal can be outside depending on quantitative index jamming thread. When difference between torque at contact of benches and torque on the limits of yield point, that is, the torque value at contact of benches, is sufficiently large, a space in the range of tightening torque. As a result, simplified control of tightening torque. Therefore, in addition to the above described property removing skewness, is required threaded joint for pipe or branch pipe with different properties at action of torque.

[0012] The, after manufacturing of pipe for oil well is transported some vehicle or kept on storage some time prior to the beginning of application. Transportation and storage pipe for oil well can continue long time. In addition, storage pipe for oil well may pass open air. Passes for storage when long time open air, rust occurs threaded connection pipe oil field assortment and score resistance and gas impermeability of threaded joint for pipe oil field assortment can decrease. Therefore, in addition to the above described resistance to the score, from threaded joint for pipe oil field assortment required different anticorrosive property, even when in cold zone, frying zone and in tropics, at atmospheric temperatures in the range of about -20 theoretically + 50 theoretically, and also in extremely cold zone, where atmospheric temperature may make up -60 theoretically to -20 theoretically.

[0013] On contact surfaces (threaded section and not having thread metal section) is formed lubricating coating for improving resistance to the score. As described above, when pipe for oil well stored in open air, on pipe for oil well can much is multiple to effect high temperature and low temperature. At much multiple action of high temperature and low temperature, adhesive capacity of lubricating coating can decrease. Shrunk adhesive capacity of lubricating coating leads to peeling of lubricating cover during tightening. Peeling of lubricating coating leads to WiFi client continuously agreed to properties of removing skewness threaded joint for pipe or branch pipe, additionally results increased torque at contact of benches. Therefore, for threaded joint for pipe or branch pipe, is required high adhesion capacity of solid lubricating coating even in version action much multiple changes in temperature in the.

[0014] In the threaded joint for pipe or branch pipe, open in patent literature 1, layer ζη or layer of alloy ζη is porous. Along this cause of adhesive capacity of layer with solid lubricating coating is satisfactory, providing sufficient score resistance. Together with the, due to porosity, gap arises between layer of ζη or alloy ζη and base material. Along this cause of, base material on section of gap can be subjected to corrosion for a long time.

[0015] Threaded joint for pipe or branch pipe, the described in Patent literature 2, has adhesive ability and lubricating properties magnificent solid lubricating coating at application in environment normal temperature. Along this cause of threaded joint for pipe or of branch pipe has sufficient score resistance in surrounding medium of normal temperature. Together with the, ambient temperature, where is used threaded joint for pipe or branch pipe, can be high or low. Base material and solid lubricating coating threaded joint for pipe or branch pipe have differing coefficients of thermal expansion. Along this cause of, when the temperature of environment, where is used threaded joint for pipe or branch pipe is high, adhesive capacity of solid lubricating coating decreases. If temperature of environment, where is used threaded joint for pipe or branch pipe is high, solid lubricating coating additionally softens and is oxidized. This further reduces the adhesion power of the solid lubricating coating. The other side, if temperature of environment, where is used threaded joint for pipe or branch pipe, is very low, solid lubricating coating hardens and is made brittle. This reduces adhesion power of the solid lubricating coating. Shrunk adhesive capacity of solid lubricating coating leads to peeling or stratification solid lubricating coating, results in reduction of resistance to the score threaded joint for pipe or branch pipe. In addition, threaded joint for pipe or branch pipe may be open to high temperature during transportation and can be opened to very low temperature at use. Therefore, threaded joint for pipe or branch pipe should have high adhesion power of with solid lubricating coating, even when much is multiple is exposed to high temperature and very low temperature.

[0016] To of the present invention is to provide threaded joint for pipe or branch pipe, having different score resistance, properties at action of torque and anticorrosive properties, and also having different adhesion with lubricating coating, even at much multiple action of high temperature and very low temperature, and to provide method of production of threaded joint for pipe or branch pipe.

[0017] Threaded joint for pipe or branch pipe the present version includes nipple and coupling. Each of nipple and coupling includes a contact surface, which includes threaded section and not having thread metal contact section. Threaded joint for pipe or branch pipe has first coating layer, the second coating layer and lubricating coating. The first covering layer is formed at least on one of contact surfaces nipple and coupling from alloy and Zn-Ni system. The second coating layer is formed on the first coating layer, which is porous coating layer from ζη or alloy ζη. On the second coating layer is lubricating coating. From the side of contact surface of the first coating layer from alloy and Zn-Ni system, the second coating layer from ζη or alloy ζη and lubricating coating are laid in given order.

[0018] Method of manufacturing threaded joint pipe or branch pipe the present version is a method of manufacturing threaded joint for pipe or branch pipe, including nipple and coupling. Each of nipple and coupling includes a contact surface, which includes threaded section, and not having thread metal contact section. This method of manufacturing the present version contains stage elektropokryvaniya, stage covering covering up and stage of lubricating coating. At the stage of elektropokryvaniya is formed first coating layer from alloy and Zn-Ni system, performing treatment elektropokryvaniya on contact surface of at least one of nipple and coupling. At the stage of covering covering up treatment covering covering up is performed after forming the first coating layer for formation of the second coating layer of the ζη or alloy ζη. At the stage of lubricating coating is formed lubricating coating on the second coating layer.

[0019] Threaded joint for pipe or branch pipe the present version has a different score resistance, properties at action of torque and anticorrosive properties, and also has different adhesion with lubricating coating, even at much multiple action of high temperature and very low temperature.

[0020] On Figure 1 circuit is indicated tightening steel pipes, when there is skewing.

On Figure 2 shown diagram between number of rotations and torque in the threaded joint for pipe or branch pipe.

On Figure 3 is indicated circuit configuration threaded joint for pipe or branch pipe the present version.

On Figure 4 it is shown section threaded joint for pipe or branch pipe the present version.

On Figure 5 it is shown section contact surface threaded joint for pipe or branch pipe the present version.

[0021] Present version of realisation is described below specifically with a reference to the drawings. Identical or equivalent elements are given below similar reference positions and their description is not repeated.

[0022] With respect to threaded joint for pipe or branch pipe including nipple and coupling, the inventor held different examination by bonds between resistance to the score, properties at action of torque, corrosion-resistant properties and adhesion of lubricating coating. Inventor produces the following results of research.

[0023] Indices of resistance to the score include high heat resistance and capacity removing skewness. In ordinary threaded connections for pipe or branch pipe heat resistance is sufficient, but capacity removing skewness is insufficient in some cases. On Figure 1 shown circuit, depict skewing. As shown on Figure 1, each of steel pipes 100 includes steel body 101 pipe (below in this document, simply called the main body of the) and connecting coupling 102. Coupling 102 screwed and fixed on the upper end of the main body 101. Each of steel pipes 100 includes nipple 103 on external peripheral surface on lower end (lower end of the main body 101), and coupling 104 on inner peripheral surface on the upper end (upper end of connecting sleeve 102). As shown on Figure 1, for vertical steel pipes 100 nipple 103 upper steel pipe 100 is inserted into coupling lower steel pipe 100, and tightened. This provides connection of vertical steel pipes 100 with each other.

[0024] When tightening preferable is making of tightening, when the upper steel pipe 100 and lower steel pipe 100 are coaxial. Together with the, in reality there are some cases, when, when tightening central axis of upper steel pipe 100 and central axis of lower steel pipe 100 installed not coaxially but with deviation from the axis. Said called misalignment of. When lagging is made with arising deviation from the axis, of possible occurrence of scratches above, than in the absence of skewness.

[0025] For improvement of capacity of removing skewness threaded joint for pipe or branch pipe, effective is formation of coating layer, having high hardness and high temperature of melting on contact surface, provided with threaded section and not having thread metal contact section. If covering layer has high hardness, coating layer on the contact surface of difficult damage when tightening and weakened. In addition, if covering layer has high temperature of melting, coating layer melt the resulting difficult, even at local increase of temperature at tightening and weakened.

[0026] So, in the threaded joint for pipe or branch pipe the present version on contact surface is the first coating layer, consisting of alloy and Zn-Ni system. The first coating layer preferably has porosity is less than 5%. The first coating layer, having a porosity of less than 5% can be made by treatment for production of elektropokryvaniya. Therefore, the first covering layer is layer elektropokryvanie.

[0027] Alloy and Zn-Ni system, forming the first coating layer, has high hardness and high temperature of melting. Therefore it is possible to increase the capacity of was removing skewness threaded joint for pipe or branch pipe. Zinc (ζη) has low hardness and low temperature melting as compared with copper (xi), which usually is used for covering layers. Together with the, alloy and Zn-Ni system, which is alloy ζη, has sufficiently high hardness and sufficiently high temperature of melting. Along this cause of, the first covering layer may increase capacity removing skewness.

[0028] Application of alloy and Zn-Ni system provides improving anticorrosive properties of threaded joint for pipe or branch pipe. Zinc (ζη) is base metal as compared with iron (of Fe), nickel (of Ni) and chromium (gyroscope). Therefore, when the first coating layer, containing zinc (ζη) is formed on the contact surface, coating layer corrodes instead of steel material (consumable protection). Said improves anticorrosive property threaded joint for pipe or branch pipe.

[0029] The, for improving lubricating properties of is usually formed lubricating coating on the contact surface of threaded joint for pipe or branch pipe. Lubricating coating can be any from solid lubricating coating and liquid lubricating coating. Adhesive capacity of lubricating coating can decrease at much multiple action of high temperature and low temperature. Lubricating coating having reduced adhesion power of, sustaining when threaded joint for pipe or branch pipe tightened and loosened. In particular, in version, where tightening is arising skewness, lubricating coating inclined to to peeling. Peeling of lubricating coating leads to WiFi client continuously agreed to lubricating properties of threaded section threaded joint for pipe or branch pipe.

[0030] The first covering layer is layer electrolytic covering up, so having flat surface. Therefore, when is formed solid lubricating coating on the first coating layer, adhesive capacity of lubricating coating is subjected to reduction.

[0031] So, on the first coating layer is porous the second coating layer from ζη or alloy ζη, and is lubricating coating on the second coating layer. In this case adhesive capacity of lubricating coating increased. The second coating layer is more porous, than the first coating layer. The second coating layer preferably has porosity of 5 - 80%. The second coating layer, more porous, than the first coating layer, may be made by treatment of covering covering up. Therefore, the second coating layer is layer, obtained mechanical by the covering. The second coating layer, which covering layer covering up, includes roughness on its surface. When is lubricating coating on surface of, having roughness, adhesive capacity due to increased of so-called anchor effect. To increase the nnaya adhesive capacity of lubricating coating prevents peeling of lubricating coating even in case of much fold action of high temperature and low temperature. If peeling of lubricating coating suppressed, high lubricant properties are preserved at the tightening and weakened. Therefore, capacity removing skewness threaded joint for pipe or branch pipe additionally increased.

[0032] In addition, if high lubricant properties threaded joint for pipe or branch pipe are preserved, torque on the limits of fluidity when tightening grows. On fig..

2 shown diagram between number of rotations and torque in threaded section threaded joint for pipe or branch pipe. As shown on fig.. 2, when nipple and coupling tightened, sections benches nipple and coupling includes in contact with each other. Torque, caused in the given point referred torque at contact of benches. When tightening threaded sections threaded joint for pipe or branch pipe, after the, as torque reaches torque at contact of benches, lagging is additionally to completion of tightening. Said increases gas impermeability sections between threaded sections threaded joint for pipe or branch pipe. When lagging is additionally, metal, forming at least one nipple and coupling begins to plastic deformation. Torque, caused in the given point, called torque on the limits of fluidity.

[0033] Torque on completion of tightening (torque tightening) is set, to produce sufficient pressure sealing at the joint, irrespective of quantitative index jamming thread. When the value of torque at contact of benches, difference between torque at contact of benches and torque on the limits of fluidity, sufficiently rather, a space in the range of tightening torque. As a result, simplified adjustment tightening torque. Preferably, torque on the limits of yield point is not too low. Sufficiently high adhesion capacity of lubricating coating provides maintenance high-torque on the limits of fluidity even when lagging and attenuation is repeated. That is, adjustment tightening torque remains simple even after much fold application, showing different properties at action of torque.

[0034] Threaded joint for pipe or branch pipe, the present version, based on indicated above of results of study includes nipple and coupling. Each of nipple and coupling, has contact surface, which includes threaded section and not having thread metal contact section. Threaded joint for pipe or branch pipe has first coating layer from alloy and Zn-Ni system, on the contact surface of at least one nipple and coupling, porous the second coating layer from ζη or alloy ζη, on the first coating layer, and also lubricating coating on the second coating layer. Layers are laid in following order from the side of contact surface: the first coating layer, the second coating layer and lubricating coating.

[0035] Threaded joint for pipe or branch pipe the present version includes the first coating layer on its contact surface. Alloy and Zn-Ni system, forming the first coating layer, has high hardness and high temperature of melting. Along this cause of threaded joint for pipe or of branch pipe has different capacity of removing skewness. In addition, alloy and Zn-Ni system acts, as consumable protective layer. Therefore threaded joint for pipe or branch pipe the present version also has different anticorrosive property. Threaded joint for pipe or branch pipe the present version additionally includes the second coating layer between the first covering layer and lubricating coating, the second coating layer consists of ζη or alloy ζη. The second coating layer is more porous, than the first coating layer. Along this cause of adhesive capacity of lubricating coating on threaded joint for pipe or branch pipe is increased as compared with version, where lubricating coating is formed directly on the first coating layer. The second coating layer is porous, showing sufficient value of torque at contact of benches and showing different properties at action of torque.

[0036] The second coating layer is layer covering covering up, obtained by treatment of covering covering up. Treatment of examples covering covering up include blasting treatment with application of metal particles for covering up. In this case ready the second coating layer is porous, and its surface has roughness.

Therefore, adhesive capacity of lubricating coating increased due to anchor effect. Treatment for covering covering up can be carried out other, well known, aroma similar to methods, other than shot blasting with application of metal particles.

[0037] Porosity of the second coating layer is, preferably, 5 - 80% and, more preferably, 10 - 60%.

[0038] Preferably, the first coating layer has a thickness of 1 - 20 mcm, the second coating layer has thickness 2 - 30 mcm, and lubricating coating has thickness of 5 - 50 mcm.

[0039] Method of manufacturing threaded joint for pipe or branch pipe the present version is a method of manufacture of above described threaded joint for pipe or branch pipe. This method of manufacturing contains stage elektropokryvaniya, stage covering covering up and stage of lubricating coating. At the stage of elektropokryvaniya, processing is performed elektropokryvaniya for forming the first coating layer, consisting of alloy and Zn-Ni system, on the contact surface of at least one nipple and coupling. At the stage of covering covering up processing is performed covering covering up after formation of the first coating layer for formation of the second coating layer, consisting of ζη or alloy ζη. At the stage of lubricating coating is formed lubricating coating on the second coating layer.

[0040] Is described below detailed description threaded joint for pipe or branch pipe and method of manufacturing threaded joint for pipe or branch pipe the present version.

[0041] [Threaded joint for pipe or branch pipe]

Threaded joint for pipe or branch pipe includes nipple and coupling. On Figure 3 it is shown side, partially in the form of section, threaded joint for pipe or branch pipe 50 the present version. As shown on fig.. 3, threaded joint for pipe or branch pipe 50 includes steel body 1 pipe (below in this document called simply the main body of the) and connecting clutch 2. on both ends of the main body 1, is made nipple 3, which includes external threaded section on its outer surface. On both ends of connecting sleeve 2 is made clutch 6, which includes internal threaded section on its inner surface. By means of tightening nipple 3 and coupling B coupling 2 are attached to end of the main body 1. also, there is a threaded connection integral-type for pipes oil field assortment, which do not include a coupling 2, but includes nipple 3, the unit provided on one end of the main body 1 and coupling b on the other end. Threaded joint for pipe or branch pipe the present version there is for both, threaded joints type of connecting sleeve for pipe or branch pipe and threaded joints integral-type for pipe or branch pipe.

[0042] On Figure 4 it is shown section nipple and coupling threaded joint for pipe or branch pipe 50 the present version. As shown on fig.. 4, nipple 3 includes contact surface. Contact surface of is section, which contacts, when nipple 3 and coupling B tightened. Contact surface of includes threaded section (external thread) 4 and not having thread metal contact section. Non-threaded metal contact section is formed on the front end of nipple 3, including metal sealing section 8 and section 9 bench. Similarly, clutch b includes contact surface. Contact surface of includes threaded section (inner thread) 5 and not having thread metal contact section (metal sealing section 10 and section 9 bench 11). When nipple 3 and coupling B tightened, both sections benches (sections 9 and 11 benches), both metal sealing section (metal sealing sections 8 and 10) and both threaded sections (external threaded section 4 and internal threaded section 5) come in contact with each other, respectively.

[0043] On Figure 5 it is shown section contact surface threaded joint for pipe or branch pipe 50 the present version. As shown on fig.. 5, threaded joint for pipe or branch pipe 50 includes on the contact surface of at least one of nipple 3 and coupling b, the first coating layer 21, the second coating layer 22 and lubricating coating 23, in this order from the side of contact surface.

[0044] [The first coating layer 21]

The first coating layer 21 is made on contact surface of at least one of nipple 3 and coupling B. The first coating layer 21 is layer elektropokryvanie, consisting of alloy and Zn-Ni system. The first coating layer 21 has high hardness and high temperature of melting. Therefore increased capacity removing skewness threaded joint for pipe or branch pipe 50. In addition, since ζη, contained in the first coating layer 21, is base metal, are enhanced anticorrosive property threaded joint for pipe or branch pipe 50.

[0045] Alloy and Zn-Ni system, forming the first coating layer 21, has ζη and Ni, and the balance in it are impurities. Impurities are, for example, of Fe, s-, about, with and T. U. Preferable content of ζη in alloy and Zn-and-Ni is 85% by mass and, more preferably, 90% by mass. The preferable content of Ni in alloy and Zn-and-Ni is 10 - 15% by mass. The first coating layer 21 has a great content of ζη, that high efficient in protection of consumable.

[0046] Content of ζη and Ni in layer 21 of the first alloy is measured as follows. Content of ζη and Ni, for example, is measured, of a hand x-ray fluorescence analyzer (Olympus takes dp2000, the Delta brand name the Premium). Any four position (any of positions 0 °C, 90 °C, 180° and 270° on direction along circumference of pipe) on the surface of metal sealing section, which is covered by a layer of alloy and Zn-Ni system, is measured for analysis of composition. Measured content of ζη and Ni is measured by means of mode measurements alloy.

[0047] Preferable thickness of the first coating layer 21 is 1 - 2 0 mcm. If the first coating layer 21 has thickness 1 mcm or more, it is possible more stable was to increase the capacity of removing skewness and anticorrosive properties of threaded joint for pipe or branch pipe 50. If the first coating layer 21 has thickness 20 mcm or less, adhesive capacity of of the first coating layer 21 additionally is stabilized. Therefore preferable thickness of the first coating layer 21 is 1 - 20 mcm.

[0048] Thickness of the first coating layer 21 is measured by the following method. Probe in the form of device measuring thickness of film phase the overcurrent, corresponding requirements to ISO (the International Agriculture Organization for Laptops certificates) 21968 (2005), is brought in contact with contact surface, made with the first covering layer 21. Is measured phase difference between high frequency magnetic field on primary side of probe and sverkhtokom, which is caused high frequency magnetic field on the first coating layer 21. This phase difference is converted to thickness of the first coating layer 21. In measurement of film thickness on threaded joint, is measured any four position (any of 0 °C, 90 °C, 180 °C, 270° positions on direction along circumference of pipe) on metal the sealing section.

[0049] Porosity of the first coating layer 21 is, preferably, less than 5%. When covering layer is made by treatment of elektropokryvanie, coating layer has porosity is less than 5%. "Porosity" layer, obtained elektropokryvaniem, includes sections of space, such as micro, sections cavities between small particles and sections of holes inside body mass from particles, which are coating layer.

[0050] Porosity of the first coating layer 21 may be measured by known method.

[0051] [The second coating layer 22]

The second coating layer 22 is made on the first coating layer 21. The second coating layer 22 consists of ζη or alloy ζη. That is, the second coating layer 22 has ζη or alloy ζη, the balance are impurities. Impurities are, for example, of Fe, s-, about, with, or T. U. Alloy ζη means alloy, content ζη 50% or more. Alloy ζη is, for example, alloy and Zn-Fe-. The second coating layer 22 may be covering layer, consisting of pure ζη and impurities or can be covering layer, consisting of alloy ζη and impurities. Content of ζη in alloy ζη can be measured, as content of ζη in the first coating layer 21.

[0052] The second coating layer 22 is porous in comparison with the first covering layer, and has roughness on its surface. Lubricating coating 23 hardens in insertion into roughness, and at the same time adhesive capacity of lubricating coating 23 due to increases of so-called anchor effect, increasing dolgovechno st lubricating coating. Therefore, even in version, where threaded joint for pipe or branch pipe 50 is subjected to much multiple of tightening and weakening, peeling of lubricating coating 23 suppressed. In addition, even in version, where lubricating coating 23 due to worn out much multiple tightening and attenuation of threaded joint for pipe or branch pipe 50, part of lubricating coating 23 or products of wear of lubricating coating 23 remain inside (in pores) of the second coating layer 22. therefore threaded joint for pipe or branch pipe 50 retains high lubricant properties.

[0053] The second coating layer 22 is layer covering covering up, made in treatment of covering covering up. Mechanically obtained coating layer is more porous, than the layer of, elektropokryvanie. Porosity of the second coating layer 22, made treatment for covering covering up, is, for example, 5 - 80%. Porosity of the second coating layer 22 can be measured, as above said porosity of the first coating layer 21.

[0054] Preferable thickness of second coating layer 22 is 2 - 3 0 mcm. If the second coating layer 22 has thickness 2 mcm or more, it is possible more stable production of adhesive capacity of lubricating coating 23 and suitable torque at contact benches with lubricating coating 23. By contrast, if the second coating layer 22 has thickness greater than 30 mcm, above described effect is neutralized. Therefore, preferable thickness of second coating layer 22 is 2 - 30 mcm. Thickness of the second coating layer 22 can be measured, as above said thickness of the first coating layer 21.

[0055] [Lubricating coating 23]

Lubricating coating 23 is made on the second coating layer 22. due to lubricating coating 23 increased lubricant properties threaded joint for pipe or branch pipe 50. Lubricating coating 23 can be solid lubricating coating or liquid lubricating coating. Preferably, lubricating coating 23 is solid lubricating coating. As lubricating coating 23, can be used known materials. Lubricating coating 23 has, for example, lubricating particles and binding substance. Lubricating coating 23 may contain solvent and other components, if necessary.

[0056] Lubricating particles is reduced coefficient of friction surface lubricating coating 23. Lubricating particles do not have restrictions in nomenclature, if have lubricant properties. Lubricating particles may be, for example, graphite, molybdenum disulfide (transistor₂ ), tungsten disulfide (WsQi₂ ), boron nitride (graininess), polytetrafluoroethylene (PTFE), fluorinated graphite (CFx), calcium carbonate ([sas 0₃ ), or their combination. Preferably, is used graphite, fluorinated graphite, transistor₂ and PTFE. When mass lubricating film 23 is taken the 100%, content of lubricating particles is, preferably, 5 - 40% by mass.

[0057] Binding substance binds lubricating particles in smazyvayushchem coating 23. As binder substance can be used organic resin, inorganic resin or their mixture. In version of application organic resin can be used termootverzhdaemuyu resin or thermoplastic resin. Thermoset resin include, for example, epoxy resin, polyimide resin, polikarbodiimidnuyu resin, polyether resin, poliefirketonovuyu resin, phenol resin, furan resin, carbamide resin and acrylic resin. Thermoplastic resin include, for example, polyamidimide resin, polyethylene resin, polypropylene resin, polystyrene resin and etilenvinilatsetatnuyu resin.

[0058] In case of use inorganic resin, as binding substance, can be used polimetalloksan. Polimetalloksan relates to high molecular polymers, having main framework main chain, made from repeating metallokislorodnykh links. Preferably, is used polititanoksan (of Ti-O-) and polysiloxane (of Si-O-). Data inorganic resin is obtained, subjecting metallalkoksidy hydro analyses and condensation. Alkoxy metallalkoksida is, for example, lower alkoksigruppoi such as methoxy group, the ethoxy-group, the propoxy-group, isopropoxy group, the isobutoxy-group, the butoxy-group, and tert - the butoxy-group. If accept mass lubricating film 23 the 100%, content of binder is, preferably, 60 - 95% by mass.

[0059] When it is required dissolving or dispersing lubricating particles and binding substance, is used solvent. Solvent not has specific limitations, if can subject components of lubricating coating 23 dispersion or dissolving. As solvent can be used organic solvent or water. Examples of organic solvent include toluene and isopropyl alcohol.

[0060] Lubricating coating 23 can contain other components, if necessary. Components of other examples include anticorrosive additive, corrosion inhibitor, surface - active substance, paraffin, friction modifier, pigment and T. U. Content of lubricating particles, binder, solvent and other components is set depending on situation.

[0061] Lubricating coating 23 is made by application and hardening the above described composite material on contact surface of at least one of nipple 3 and coupling 6.

[0062] As shown on fig.. 3, in version of threaded joint for pipe or branch pipe 50, in which nipple 3 and coupling B tightened before delivery, lubricating coating 23 can be executed on only on one of contact surfaces of nipple 3 and coupling B before tightening. In this case on connecting coupling 2, of small length flying to make application of composite than on the main body 1, large length. Preferably therefore of lubricating coating 23 on contact surface coupling B connecting sleeve 2. in the threaded joint for pipe or branch pipe 50 on the front end section of pipe, where nipple 3 and coupling b are not tightened before delivery, lubricating coating 23 may be made on both contact surfaces of nipple 3 and coupling b, the contact surfaces is anticorrosive property, and also lubricant properties. Alternatively, lubricating coating 23 may be made only on one of contact surfaces of nipple 3 and coupling b, and on the other contact surface may be made solid anticorrosive coating, proposed below. In both cases it is possible giving thread resistance to the score, gas permeability and anticorrosive properties.

[0063] Preferable is closing the whole contact surface of at least one of nipple 3 and coupling 6 lubricating coating 23. Only section of contact surface (for example, only sealing sections 8 and 10) can be close lubricating coating 23.

[0064] Lubricating coating 23 single layered or much sloinym. Term "much sloinyi" relates to state, where lubricating coating 23 assembled from two or more layers, applied one after another from the side contact surface. Repetition of application and hardening composite provides packages of lubricating coating 23 from two or more layers. Lubricating coating 23 may be made directly on contact surface or may be made after development treatment of, described by below.

[0065] Is preferable thickness of lubricating coating 23, component 5 - 50 mcm. If lubricating coating 23 has thickness 5 mcm or more, possible stable production of high lubricating properties of. The, if lubricating coating 23 has thickness 50 mcm or less, adhesive capacity of lubricating coating 23 stabilized. In addition, if lubricating coating 23 has thickness 50 mcm or less, threaded tolerance (gap in thread) sliding surface expands, that reduces pressure on the joint of at. The, can be to exclude excessive increased tightening torque. Therefore preferable thickness of lubricating coating 23 is 5 - 50 mcm.

[0066] Thickness of layer 23 of lubricating coating is measured as follows. At similar conditions with version application of layer 23 of lubricating coating on threaded joint for pipe or branch pipe film lubricant is applied on a flat plate. Among conditions for coating threaded joint for pipe or branch pipe and flat plate, should be observe the following conditions; the distance between the object application of coating and tip nozzle, injection pressure, composition viscosity, speed of application of coating, and T. U. For coincidence viscosity composition, temperature tank, pipe and discharge nozzle should be agree between threaded joint for pipe or branch pipe and plate. From the difference weight plates to application of composition and weight of plate after applying of composition is calculated quantity of the composition, applied per unit of time. Composition is hardened on plate for forming of the layer 23 of lubricating coating. Thickness of layer 23 of lubricating coating is measured, of a meter of film thickness. From difference weight plates to application of composition and weight plate after applying of composition is calculated weight layer 23 of lubricating coating. From film thickness and weight layer 23 of lubricating coating, is calculated density layer 23 of lubricating coating. Then form and size to the thread (inner diameter and thickness, and T. U.), calculated area of threaded joint pipe or branch pipe for applying coating layer. Calculating area for applying coating layer corresponds to area scanning thread, converts three-dimensional surface in flat surface. From time application of composition on threaded joint for pipe or branch pipe, rated area application and density layer 23 of lubricating coating, calculate the average thickness of layer 23 of lubricating coating on threaded joint for pipe or branch pipe.

[0067] [Solid anticorrosive coating]

The above described threaded joint for pipe or branch pipe 50 may include lubricating coating 23 on the contact surface of one nipple 3 and coupling 6 and may include solid anticorrosive coating on contact surface of the other from nipple 3 and coupling 6. as described above, threaded joint for pipe or branch pipe 50 may be stored long time till its actual application. In this case the solid of anticorrosive coating increases anticorrosive property nipple 3 or coupling 6.

[0068] Examples of solid anticorrosive coating include khromatnoe coating consisting of chromate. Khromatnoe coating is known by treatment of compounds of trivalent chromium.

[0069] Solid anticorrosive coating is not limited khromatnym coating. The other solid anticorrosive coating contains, for example, hardened by ultraviolet radiation resin. In this case, solid anticorrosive coating has strength, with which solid anticorrosive coating not it is crushed force, applied to it at installation of the tread. In addition, during transportation or storage of solid anticorrosive coating not dissolved, even when open action of water, condensing in dew point. In addition, solid anticorrosive coating practically not gets softened even at high temperature is more than 40 theoretically. Hardened by ultraviolet radiation resin is conventional based composite resin. Hardened by ultraviolet radiation resin not is limited by content of a specific monomer, oligomer and photoinitiator and induces photopolymerization reaction at irradiation with ultraviolet light for forming hardened coating.

[0070] On the other contact surface threaded joint for pipe or branch pipe 50, may be made coating layer, and on coating layer, may be made the above described solid anticorrosive coating. Alternatively, solid anticorrosive coating may be made directly on the other contact surface.

[0071] [Base material threaded joint for pipe or branch pipe 50]

Composition base material threaded joint for pipe or branch pipe 50 has no specific limitations. Examples base material threaded joint for pipe or branch pipe 50 include carbon steel, stainless steel steel and steel alloys. Among steel alloys, high strength steel alloys such as diphasic stainless steel steel, containing such alloying elements, as of Cr, Ni and Mo, and alloys of Ni, have high anticorrosive property. Therefore data high strong steel alloys, as base material threaded joint for pipe or branch pipe 50, gives different anticorrosive properties in corrosion environment, containing hydrogen sulfide, carbon dioxide and T. U.

[0072] [Method of manufacturing]

Below is described description of method for manufacturing of threaded joint for pipe or branch pipe 50 the present version.

[0073] Method of manufacturing threaded joint for pipe or branch pipe 50 the present version includes stage elektropokryvanie, stage covering covering up and stage of lubricating coating.

[0074] [Stage elektropokryvanie]

At the stage of elektropokryvanie processing is performed for elektropokryvanie for forming the first coating layer 21 on contact surface of at least one of nipple 3 and coupling B. Treatment for elektropokryvanie is conventional method. For example, treatment for elektropokryvanie is by method, in which contact surface of at least one of nipple 3 and coupling B is immersed in electrolytic bath, containing zinc ions and nickel ions and include power supply. Electrolytic bath, are of series there are in sale. Electrolytic bath preferably contains ions of zinc: 1 - 100 g/l and nickel ions: 1 - 50 g/l. Can be installed suitable conditions treatment of elektropokryvanie. Treatment of conditions elektropokryvanie are the following, for example, pH of electrolytic bath: 1 - 10, temperature electrolytic bath: 10 - b0°s, current density: 1 - 100 and/dm² and treatment time: 0.1 - 30 minutes. As described above, preferable thickness of the first coating layer 21 is 1 - 20 mcm.

[0075] [Stage covering covering up]

At the stage of covering covering up, is dry treatment covering covering up for formation of the second coating layer 22, which is layer covering covering up, on the first coating layer 21. By dry covering covering up is, for example, method of shot blasting covering up, in which peen device is used to provide for collisions of particles with object covering up. The present version, the covering may be made only on contact surface. Therefore, method of shot blasting covering up, which provides partial of covering up, is suitable.

[0076] Particles, used in dry method covering covering up, such as method of shot blasting covering up, are metal particles, which comprise a ζη or alloy ζη at least on its surface. Particles may be metal particles, completely consisting of ζη or alloy ζη. Preferable medium jet is created from particles, core of which contains Fe or alloy Fe used in patent literature 1, with surface coated with layer of ζη or alloy ζη, for example alloy of Zn-Fe-. Particles are and sold, for example, under brand entitled "Z of the Iron" company DOWA the Iron Powder Industries of with ., Ltd.. Preferable particle size is 0.2 - 1.5 mm.

[0077] When metal particle, having core made of Fe or alloy Fe, surface of which is coated ζη or alloy ζη is used in shot-blasting threaded joint for pipe or branch pipe 50, only ζη or alloy ζη coating layer particles sticks to steel pipe. The is created the second coating layer 2, which is layer covering covering up from ζη or alloy ζη on the first coating layer 21. Covering layer covering up is porous, its porosity is 5 - 80%. Along this cause of the lubricating coating 23 and solid anticorrosive coating on the second coating layer 22 additionally increases adhesive capacity of lubricating coating 23 and solid anticorrosive coating due to of so-called "anchor effect". As described above, preferable thickness of second coating layer 22 is 2 - 30 mcm.

[0078] [Step for lubricating coating]

After the stage of covering covering up is step for lubricating coating. At the stage of lubricating coating purpose composite for creation of lubricating coating (below in this document, also called composite). Composite produced by mixing described above lubricating particles and binder. Composite may additionally contain described above solvent or other components.

[0079] Prepared composite is applied on the second coating layer 22. method of applying not has specific limitations. For example, composite, containing solvent, is deposited on the second coating layer 22, of a pistol - sprayer. in this case composite is uniformly applied to the second coating layer 22. nipple 3 or coupling b, on which composite is sprayed, dried or dried heating. Drying heating is, for example, by means of series of tapped and available in sale of equipment direct drying or T. U. Said leads to solidifying composite for formation of solid lubricating coating 23 on the second coating layer 22. conditions for drying heating can be to install suitable boiling temperature, melting temperature, and T. U. of each component, contained in the composite, received into account.

[0080] In version, where is used composite, not containing solvent, for performing lubricating coating 23, can be used method of preparing melt, for example. In the method of preparation of melt composite is heated for transition fluid state. Composite collected in flowing state is sprayed pistoletomraspylitelem with function of maintaining temperature. Composite the is uniformly applied to the second coating layer 22. heating temperature composite can be establish corresponding to temperature of melting and softening the above described binding substance and other components, received into account. Nipple 3 or coupling b, on which composite is applied, is cooled with air or T. U. Said leads to solidifying composite for formation of lubricating coating 23 on the second coating layer 22.

[0081] [Of solid anticorrosive coating (treatment based on compounds of trivalent chromium)]

As described above, stage elektropokryvanie, stage covering covering up and stage of lubricating coat is made on the contact surface of one nipple 3 and coupling B, for forming the first coating layer 21, the second coating layer 22 and lubricating coating 23.

[0082] The, on contact surface of the other from nipple 3 and coupling b can be perform first coating layer 21, the second coating layer 22 and lubricating coating 23 or covering layer and/or solid anticorrosive coating. Below is described description of versions, where the first coating layer 21 and solid anticorrosive khromatnoe coating is formed on contact surface of the other from nipple 3 and coupling B.

[0083] In this case the first coating layer 21 is formed, performing described above stage elektropokryvanie. After stage of elektropokryvanie is treated trivalent chromate for forming solid anticorrosive coating. Treatment based on compounds of trivalent chromium is treatment for forming the coating based on compounds of trivalent chromium (khromatnoe coating). Khromatnoe coating, made by treatment based on compounds of trivalent chromium, suppresses white rust on the surface of coating layer from alloy ζη. This improves appearance article (together with the, white rust on coating layer from alloy ζη is not rust threaded joint for pipe or branch pipe 50 and does not effect on score resistance and anticorrosive properties of threaded joint for pipe or branch pipe 50). Treatment based on compounds of trivalent chromium may be made conventional method. For example, contact surface of at least one of nipple 3 and coupling B is immersed in liquid st for treatment of chromate, or liquid st for treatment of chromate is sprayed for applying on contact surface. Then, contact surface is washed. Contact surface can be rinse after immersion in liquid st for treatment of chromate and power supply. Contact surface, on which is applied liquid st for treatment of chromate can be dried heating. Can be to install suitable conditions for treatment of based on compounds of trivalent chromium.

[0084] [Stage the preprocessing]

In described above stages of manufacturing stage of the preprocessing can be carried out before stage elektropokryvanie, if necessary. Examples stages the preprocessing include protravku and alkaline degreasing. At the stage of the preprocessing washed off oil and T. U ., prilipshee to contact surface. The preprocessing stage may additionally include treatment by grinding, such as mechanical finishing of surface polishing.

[0085] Upon completion of above described stages of manufacturing is obtained threaded joint for pipe or branch pipe 50 the present version.

[0086] Examples are described below. It should be mentioned, that the present invention is not limited examples. In examples contact surface called nipple of nipple, and contact surface of coupling called surface coupling. In addition, icon " %" in examples means percentage by mass, or other if specially not as indicated.

[0087] In true examples applied threaded steel pipe entitled VAM21 (of R) firm Steel is & SUMITOMO of Metal Corporation is. Steel pipe VAM21 (of R) has been steel pipe with outer diameter 24.448 cm (9 - 5/8 inches) and thickness of wall 1.199 cm (0.472 inch). Steel pipe is is made of carbon steel, the following chemical composition with: 0.21%, of Si:

0.25%, MP: 1.1%, P: 0.02%, s-: 0.01%, xi: 0.04%, of Ni: 0.06%, gyroscope:

0.17% and Mo: 0.04%, and the balance were of Fe and impurities.

[0088] Surface of nipple and surface of coupling, for which applied steel pipe of each number testing, claimed mechanical finishing surface polishing (surface roughness 3 mcm). Then fulfil covering layers (the first and second covering layers) or coating (solid anticorrosive coating, lubricating coating), shown in the table 1, for preparation of nipple and coupling of each number testing.

[0089] Table 1

I (12μκμ) method of covering layers or coatings was the following. In each number of testing porosity measured by known method. Porosity layers, elektropokryvanie, was less than 5%, and porosity dry layers of covering covering up is 5 - 80%. Porosity of layer of manganese - phosphating was less than 30%.

[0091] [Test number 1]

For testing number 1 on surface of nipple fulfilled elektropokryvanie and Zn-Ni system (DaiwaFineChemicalsCo., Ltd.), for forming the first coating layer with thickness of 8 mcm. Conditions elektropokryvanie were the following: pH of electrolytic bath:

6.5, temperature electrolytic bath: 25 theoretically, current density: 2 and/dm² and treatment time: 18 minutes. Composition of the first coating layer has been ζη: 85% and Ni: 15%. In addition, obtained the first coating layer processed based on compounds of trivalent chromium. Liquid st for treatment of based on compounds of trivalent chromium occurred trading mark "DAINChromate Eco RI-and-02", manufacturer DaiwaFineChemicals with ., Ltd.. Conditions for treatment of based on compounds of trivalent chromium were pH in bath: 4.0, temperature in bath: 25 theoretically and treatment time: 50 seconds.

[0092] In conditions identical with conditions for surface of nipple fulfilled the first coating layer on the surface of coupling. Then fulfilled the second coating layer dry treatment covering covering up (method of shot blasting covering up). In dry treatment covering covering up, applied metal particles with coating from alloy of Zn-Fe-. Obtained the second coating layer that average thickness film 10 mcm. On surface of coupling with the first covering layer and second covering layer, made on it, inflicted composite for forming solid lubricating coating. Composite for forming solid lubricating coating chief graphite 5% by mass, PTFE 4% by mass and PFPE 10% by mass. Composite for forming solid lubricating coating was heated UP to 130 theoretically for spraying and was for performing solid lubricating coating with average thickness film 30 mcm.

[0093] [Test number 2]

For testing number 2, of nipple subjected the same treatment with test number 1. first obtained coating layer that film thickness and chemical composition similar obtained in testing number 1. thickness of coating based on compounds of trivalent chromium has been is installed the same with obtained in testing number 1. on surface of coupling, the first covering layer and the second coating layer have been are made, as in testing number 1, and then inflicted composite for forming solid lubricating coating under brand name "khu1ap1425". Composition branding names "khu1ap1425" chief epoxy resin, 22% weight, particles PTFE, 9% weight, solvent, 18% by mass of the whole, pigment and water, 40% by mass. Composite for forming solid lubricating coating sprayed for applying on surface of coupling, and then subjected to drying with heating (at 90 theoretically, five minutes) and processing for hardening of (at 210 theoretically 20 minutes) for forming solid lubricating coating. Produced solid lubricating coating had average thickness film 30 mcm.

[0094] [Test number 3]

For testing number 3 layers covering the first and second covering layers have been are made on the surface of nipple and surface of coupling, as on the surface of coupling testing number obtained 1. first and second covering layers have film thickness and chemical composition identical with test number 1. then on surface of nipple caused the following composite for forming solid lubricating coating. Composite for forming solid lubricating coating is composite, produced and sold under brand name "DEFRICCOAT 405" company Kawamura Research isthe Lab., Inc., containing molybdenum disulfide and graphite in inorganic polymer binder. Composite for forming solid lubricating coating sprayed for applying on surface coupling and then was on air three hours. Then composite subjected action hot wet air at 150 theoretically ten minutes. Produced solid lubricating coating had average thickness film 20 mcm. On surface of coupling fulfilled solid lubricating coating, as on the surface of coupling testing number 2. produced solid lubricating coating had equal thickness and chemical composition with coating surface of coupling testing number 2.

[0095] [Test number 4]

For testing number 4 the first coating layer and coating based on compounds of trivalent chromium have been are made on surface of nipple, as on surface of nipple testing number 1. made coating layer and coating imelie thickness, similar with test number 1. on surface of coupling were the second coating layer, as on the surface of coupling testing number 1. obtained the second coating layer that average thickness film 10 mcm. On obtained the second coating layer is made of the solid lubricating coating, as on the surface of coupling testing number 2. produced solid lubricating coating had equal thickness and chemical composition with coating surface of coupling testing number 2.

[0096] [Test number 5]

For testing number 5 on the surface of the nipple have been are made the first coating layer and coating based on compounds of trivalent chromium, as and on the surface of nipple testing number 1. made coating has a thickness equal with thickness testing number 1. on surface of coupling were the first coating layer, as and on the surface of nipple testing number 1. made the first coating layer has thickness equal with thickness testing number 1. on obtained the first coating layer was is made solid lubricating coating, as and on the surface of coupling testing number 2. produced solid lubricating coating had equal thickness and chemical composition with coating surface of coupling testing number 2.

[0097] [Test number 6]

For testing number 6 have been are made the first coating layer and coating based on compounds of trivalent chromium on surface of nipple, as and on the surface of nipple testing number 1. Made coating layer and coating have similar thickness with layer of coating and testing number 1. on surface of coupling were the first coating layer, as in testing number 1. made the first coating layer has thickness equal with layer thickness testing number 1. surface of coupling with the first covering layer, made, on it plunged in liquid st for chemical treatment of manganese - phosphating at 80 - 95 theoretically on ten minutes, the were layer manganese - phosphating thickness 12 mcm (at surface roughness 10 mcm). On the surface of coupling with made on it layer manganese - phosphating, was is made solid lubricating coating, as in case of surface of coupling testing number 2. produced solid lubricating coating has equal thickness and chemical composition with coating surface of coupling testing number 2.

[0098] Testing for evaluation of tightening/attenuation of]

At testing for evaluation of tightening/attenuation of, evaluated score resistance and properties at action of torque. Evaluated, as score resistance, high heat resistance and capacity removing skewness.

[0099] [Score resistance: high heat resistance]

For investigating effects, tested layers on the first coating layer in high-temperature oil well, much was carried out testing multiple of tightening on nipples and couplings testing number 2 and testing number B. In particular, with nipple and coupling, tightened the first tightening, surrounding part of coupling heated to 200 theoretically on six hours belt heater. Then, nipple and coupling weakened, and repeated lagging and attenuation. Speed of tightening is about 10/min first, then about 2/min after contact benches. Torque tightening was 42.8 kN - m. Lagging and attenuation threaded joint for pipe or branch pipe fulfil at normal temperature (2 0 theoretically). Each time during cycle tightening and attenuation of visually verified occurrence of scratches due to change of tightening torque. In time moment arose when not to be repair scuff, testing finished. Results shown in the table 2.

[0100] Table 2

[Results for evaluating]

As shown in the table 2, testing of number 2, scuff not arose after the tenfold tightening and attenuation. By contrast of with said, in testing number B, layer 2 manganese - phosphating development treatment of suffered from high temperature decomposition. Said is considered to be occurred due to removal of crystalline water and occurrence of brittleness. As a result, lagging and attenuation continued without scratches to the second time, and not to be repair scuff arose in the third time, and on this testing completed.

[0102] [Score resistance: capacity removing skewness]

Repetition of tightening and attenuation of with misalignment of fulfilled on nipples and couplings testing number 1 - 6 for evaluating the capacity of removing skewness. Angle θ deviation skewness was 5°. Lagging and attenuation repeated up to ten times. Speed of tightening when tightening and weakened is about 10/min, and torque moment of tightening was 42.8 kN - m. Each time when tightening and attenuation of surface of nipple and surface of coupling verified visually. Visual observation verified occurrence of scratches. When scuff was a small and therefore maintainable, defect of scuff remontirovali, and testing continued. Measured number of passed and tie of weak until not subject to repair scratches. In the table 2 shown results.

[0103] [Results for evaluating]

As shown in the table 2, in nipples and couplings testing of numbers 1 - 3 and testing number B, scuff due to skewness not arose. This is considered to be result of improving adhesion of layer of solid lubricating coating created layers on the first coating layer. By contrast of with said, in testing number 4 and testing number 5, number of tie was considerably is reduced.

[0104] [Properties at action of torque]

Testing properties at action of torque conducted on nipples and couplings testing number 1 - 6. Specifically, the torque value at contact benches (difference between torque on the limits of fluidity and torque at contact benches) measured as follows. Nipple and coupling testing of number 1 - 6 have been prepared and tightened with application of hydro drive tube key manufacturing firm Weatherford. Even after tightening was is provided torque for tightening, the graph is built is torque Figure 2. on graph torque has been the fluid torque value at contact of benches. Torque at contact benches is value of torque while, when section of 9 bench comes in contact, and change of torque begins to deviate from the first linear zone (zone elastic deformation). The, torque on the limits of fluidity is value of torque while, when starts plastic deformation of. In particular, torque on the limits of fluidity is value of torque while, when deviation starts from the second linear zone, the second linear zone occurs after achieving torque torque at contact of benches. Here have been prepared nipple and coupling, for which layers 1 and 2 development treatment, and layers of solid anticorrosive coating testing of numbers 1 - 6 have been used and treated with layer with replacement of solid lubricating coating with consistent grease, corresponding standards of API. Received value of torque at contact of benches of this case the 100, identified value for testing number 1 - 6. In the table 2 shown rezultzaty.

[0105] [Results for evaluating]

As shown in the table 2, in tests number 1 - number 3, were are made second covering layers, which were layers covering covering up, and so the torque value on the steps exceeds the 100, showing different properties of torque. By contrast, in testing number 4 and testing number 5, torque at contact benches have been less than 100, showing low properties at action of torque. In testing number 6 layer on the first coating layer is layer of manganese - phosphating, and so the torque value at contact of benches was less than 100, showing low properties at action of torque.

[0106] [Test for evaluating anticorrosive properties:

testing with spraying of salt]

Samples were prepared with use of carbon steel same composition with tests of number 1 - 6. Samples have size 7 0 mm X 150 mm, and thickness of 1 mm. Samples are subjected to the same treatment of surfaces with tests of number 1 - 6, and was carried out on samples testing with spraying of the salt. Testing with spraying of the salt was carried out based on said method, described in the JIS ζ 2371:2000. By means of visual observation, measured moment of time, in which subject rust were stalemates on surface of sample of each number testing. Results shown in the table 2.

[0107] [Results for evaluating]

In tests number 1 - 3, testing number 5 and testing number B layers, have been elektropokryvanie are made, as the first covering layers, and rust not there. By contrast with this, in testing number 4, only the second coating layer, which is porous layer covering covering up, were immediately above contact surface, and sufficient anticorrosive effect was not is obtained, as a result of rust were stalemates on entire surface after 500 hours.

[0108] [Testing resistance to atmospheric action: testing on dolgovechno st coating (adhesion power of the lubricating coating)]

Have been prepared coupling testing number 1 - 6. Each sleeve has been cropped from end of tube, to have length 1 m. According to atmospheric conditions testing (moisture content is relative humidity) and order, shown in the table 3, conducted testing resistance to atmospheric action, where simulated all types of weather conditions in the range from extreme cold to high temperature. Surface couplings visually surveyed for checking of external appearance of solid lubricating coating (on scaling and presence/absence of rust).

[IT]

[Results for evaluating]

In testing number 1 - 3 and testing number b, have been are made both, the first and second covering layers and, therefore peeling of coating does not arisen, and rust not there. By contrast with this, in testing number 4 only the second coating layer, which is layer covering covering up, were on the surface of, and showed low adhesion power with base material, was the result of peeling coating. In addition, sufficient anticorrosive effect was not is obtained, was result of appearance of rust on entire surface after 500 hours. In testing number 5 were only the first coating layer, which is layer elektropokryvanie, indicating low adhesive capacity of with lubricating coating, result was peeling coating.

[0111] Above, invention describes variants of realization of the present invention. Versions, the described, are only for examples of practical realization of the present invention. Therefore, the present invention is not limited described above of the methods, and the described versions can be modified and practically to realize suitable method without waste from the volume of the present invention.

[0112]

3 nipple

4, 5 threaded section

b clutch

8, 10 metal sealing section

9, 11 section bench

21 the first coating layer

22 the second coating layer

23 lubricating coating

50 threaded joint for pipe or branch pipe