PROCEDURE FOR THE TREATMENT OF STEEL IN AN OXYGEN CONVERTER FOR TOP BLOWING

The invention refers to a procedure for the treatment of steel in an oxygen converter for top blowing, with which by a circulating and lance adjustable in their inclination to the vertical one the focal spot produced by blowing is moved. A such procedure comes out from the GB-PS No. 700.224 and serves the purpose to distribute the oxygen evenly over the entire surface. Thus an effective withdrawal ven carbon, sulfur and phosphorus from the melt is to be obtained. The results received so far were and/or are not satisfying yet. There is at present from there a multiplicity of procedure variants, which aim at all directly or indirectly an optimization of carbon, Schwefelund phosphorus distance, but not yet completely reached. With a beiI0 spielsweise 1583233 procedures become known by the DE-OS withdraw at the lower end the lance several gas jets in such a manner that they hit under a pointed angle the surface of the melt. Since the lance implements torsional vibrations during the blowing procedure, the points of impact of the gas jets on the surface of the melt describe Kreisb6gen. This Krelsbögen partly overlaps. It is reached that the surface of the melt is constantly and coated evenly by oxygen jets and no local overheatings to arise. The DE-AS 2110527 e.g. describes procedures, with which the lance and/or the lances, but only the Neigungswlnke does not rotate!. the oxygen jet is changeable. The brake mark is not moved thereby. A goal of the invention is a Vervoilkommnung of the procedure initially specified regarding an optimal decarburisation, desulphurisation and a Entphosphorung. This goal is achieved according to invention by it that the angle of inclination {e) the lance against the vertical one during blowing within a range from 0< e < 15° and the Umlaufzahl (v) to a value of 0< v< 15 Umdr/min it is in-steered, in such a manner that the oxygen jet the lime on the surface of the melt clinkered and the melt as well as decarburizing is desulphurised and entphosphorisiert. The nature of the invention lies in finding the fact that a good decarburisation requires other Elasbedingungen than a good desulphurisation and Entphosphorung that however optimal relations are obtained, if the peripheral speed and the inclination of the lance lie within the angegenbenen ranges the distance of carbon behave concerning s0 of the Umlaufzahl of the lance contrarily for the distance of sulfur and phosphorus. The range according to invention of the Umlaufzahl gives now for carbon, sulfur and phosphorus not in each case the optimally attainable, but for all three elements together nevertheless a very good result. How the blowing conditions affect in detail the decarburisation, desulphurisation and Entphosphorung, is more near implemented on the basis the designs and in the explanations in addition. Fig. 1 is a diagram. in that the expiration of the decarburisation reaction as a function of the time of blast is shown. Fig, 2 is a diagram. in that the extent of the decarburisation and its change by the angle of inclination of the lance are shown. Fig. S shows the extent of the change of the decarburisation in a diagram by the number of circulation of the lance per minute. Fig. the change of the extent of the Entphosphorung shows 4 as a function of the number of circulation of the lance per minute in a diagram. Fig. the change of the extent of the desulphurisation of the number of circulation of the lance per minute shows 5 in a diagram. Fig. the change of basicity shows 6 as a function of the time of blast in a diagram. Fig. the change of the extent of the desulphurisation shows 7 with a sulfur-poor steel as a function of the time of blast. Fig. the change of basicity shows 8 with strongly basic 5 a procedure as a function of the time of blast, and Fig in a diagram. the extent of the desulphurisation ((s) [of S]) shows 9 as a function of the change of basicity. With the invention only one lance is intended, the lance however can only one or several Offnungsdüsen possess. Such a lance exhibits an inclination, which can change concerning a vertical line independently. The upper end of the lance is provided with a turning mechanism, which is likewise independently propelable. The procedure in accordance with the invention is characterised in particular by that the inclination e &lt within a range from 0; < 15° lies. The effect on the extent of the decarburisation with different angles of inclination was determined, and the W.rgebnisse is in the Fig. I and 2 represented. In Fig. I amounts to the inclination of the lance 4°, and blowing takes place with a given Umlaufzahl from 5 Umdr/min. The decarburisation reaction arising with it was compared with the well-known procedure the arising. The extent of the decarburisation with proceeding in accordance with the invention corresponds approximately to that one with the well-known LD-Verfabren. Therefore the outlines of the LD-process remain with proceeding in accordance with the invention. Fig. 2 the relationship between the inclination of the lance Umlaufzahl 5 Umdr/min points) and to the extent out of the decarburisation. With increasing angle of inclination the extent of the Entkohluug decreases gradually. If the angle exceeds 150, the extent becomes very small. The preferential range of the angle of inclination is with 0< e < _-15°. The angle of inclination can be selected within the range in dependence of the shape and the I0 capacity of the converter, indicated above. A further reason for keeping this preferential range of the angle of inclination lies that the extent of the focal spot and/or blowing mark should not come with the furnace wall into contact. If such a contact is present, the furnace wall is damaged and the wear is unusually high, so that the life span considerably absinkf. The angle of inclination of the lance, if this lies within the range indicated above, lets itself amend easily as a function of the expiration of the reaction during the blowing procedure. In particular the regulation with the well-known aufund outgoing movement of the lance and by the regulation of the Umlaufbewegung of the lance takes place, with which one will deal later, so that a mild and sharp blowing are feasible according to the expiration of reaction. A further characteristic of the invention lies that the lance &lt within the range from 0; < 1 5 Umdr/min rotates (= Umlaufzahl). The influence of the Umlaufzahl and the inclination of the lance during the blowing procedure was determined. The results received thereby are in the Fig. S to 5 shown. The following procedural conditions were kept. Pund S-content of the hot metal P: 0.150%, S: 0.035% lime addition quantity: 50 kg/rS (kg per ton of melt) eccentricity relationship of the lance E __Dl. I00 (%) there whereby D,…. Diameter of the circle, which the oxygen lance describes on the Badcb8rfläohe, and D0…. Diameters of the Badoberfläehe in the furnace mean. During the designs mean: Curve path A…. = 10% curve path B…. E = 20% curve path C…. • = 40% curve path D…. = 60% the influence of the Umlaufzahl of the lance with the operating conditions indicated above was determined. The extent of the decarburisation is in Fig. 3 shown. As can be taken from this figure, the extent of the decarburisation remains the same with any eccentricity relationship up to the Umlaufzahl of the lance of 5 Umdr/min. If however the eccentricity relationship and the Umlaufzahl increase, the extent of the decarburisation decreases. Thus limit values, which in the case of the Exzentrizitätsverhä] result tnis in the case of 60% and in the case of the Umlaufzahl in the case of 15 Umdr/min lie. On the basis the Fig. the connection between the Umlaufzahl of the lance and the extent of the Entphosphorung and the desulphurisation is shown 4 and 5. It can from these figures be taken that the Entphosphorung and the Entsohwefelung in dependence of the eccentricity relationship and the Umlaufzahl improve. If however the Umlaufzahl amounts to 5 to I0 Umdr/min, the upward trend becomes weaker and with a Umlaufzahl of I0 Umdr/min the curve runs approximately horizontally. Therefore a Umlaufbewegung is almost insignificant above 15 Umdr/min for the Entphosphorung and desulphurisation. On the basis the Fig. the meaning of the choice of the Umlaufzahl the long within the range 0&lt lets itself 3 to 5; < 15 Umdr/min and the change the same in accordance with condition of the expiration of reaction clearly point out. The following percentages arise with the basic enterprise: Decarburisation 100% Entphosphorung 86% desulphurisation 33%. If a Umlaufbewegung of the lance is present with • = 60% and u = 5 Umdr/min, which lie within the range in accordance with the invention, a substantial improvement can be obtained, be inferred I0 like this the figures can. In particular amount to the decarburisation 100%, the Entphosphorung 93% and the desulphurisation 50%. This surprising blowing reaction runs off, since by the selected angle of inclination and the intended Umlaufbewegung of the lance clinker-formed de Reaktion runs off fast. The reaction for slag formation with a basicity from 3,0 to 3.5, as in Fig. 6 shown, runs off fast, so that the slag formation speed is very fast with proceeding in accordance with the invention compared with well-known approaches. The procedure in accordance with the invention was then applied to a sulfur-poor steel, and the result compared with that one in a well-known procedure determined. The results are in Fig. 7 shown. With the well-known LD-process first a S-content of 0,003% arises, which rises then to 0,005% after 4 min. Hiebei arises as well known the effect that sulfur is again developed. This structure arises even with a sulfur-poor steel. With proceeding in accordance with the invention however an increasing even desulphurisation arises. Like the Fig. 8 to infer is, is substantially faster the slag formation speed with proceeding in accordance with the invention than with the well-known approaches. The speed is so fast that the cinder already almost forms with high basicity in the first time of blast area. On the basis the Fig. 9 it is represented that (s) - relationship with proceeding in accordance with the invention than with the well-known LD-process is larger, and that the Entsohwefelungsgeschwindigkeit of cinder/molten bath is larger with a cinder with same basicity with the production of sohwefelarmem steel. The procedure in accordance with the invention made possible thus to affect by the regulation of the angle of inclination of the lance the decarburisation, desulphurisation and Entphosphorung in desired way • with proceeding in accordance with the invention does not arise stagnation or blockage by the versohlaokten Kalkzusoh g during blowing.