EP0226912A2 - Procédé de fabrication d'acier de haute qualité - Google Patents

Procédé de fabrication d'acier de haute qualité Download PDF

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Publication number
EP0226912A2
EP0226912A2 EP86116948A EP86116948A EP0226912A2 EP 0226912 A2 EP0226912 A2 EP 0226912A2 EP 86116948 A EP86116948 A EP 86116948A EP 86116948 A EP86116948 A EP 86116948A EP 0226912 A2 EP0226912 A2 EP 0226912A2
Authority
EP
European Patent Office
Prior art keywords
melt
oxygen
carbon
content
bath
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86116948A
Other languages
German (de)
English (en)
Other versions
EP0226912A3 (fr
Inventor
François Schleimer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arcelor Luxembourg SA
Original Assignee
Arbed SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Arbed SA filed Critical Arbed SA
Publication of EP0226912A2 publication Critical patent/EP0226912A2/fr
Publication of EP0226912A3 publication Critical patent/EP0226912A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/30Regulating or controlling the blowing
    • C21C5/32Blowing from above

Definitions

  • the invention relates to a method for producing high-quality steel, in the context of an oxygen inflation process.
  • high-quality is a steel that has the lowest possible levels of phosphorus, sulfur and non-metallic inclusions.
  • One method of achieving the desired carbon content in a melt is to stop decarburization in good time.
  • the disadvantage of this method is that it does not allow steels with a high carbon content and at the same time a low phosphorus content to be obtained.
  • pretreatment of the pig iron is essential.
  • Such pretreatments which are mainly explained by Japanese steel manufacturers in numerous publications, take place outside the converter, in stationary or in mobile pans and require a high level of equipment.
  • the necessary temperature losses must be accepted or compensated for by heating units.
  • the applicant has set itself the task of developing a process that allows the production of high quality steel, the content of non-metallic inclusions is reduced to a minimum.
  • the first step is decarburization in the converter, by blowing oxygen, with the addition of the necessary additives for slagging silicon and phosphorus.
  • Decarburization generates heat and the slag becomes reactive as a result of oxygen absorption, with a certain proportion of the phosphorus being absorbed into the slag.
  • the decarburization is carried out up to a carbon content below 0.10% C, preferably below 0.05% C, regardless of which carbon content is targeted in the finished steel.
  • the second step is a treatment of the essentially decarburized and oxygen-rich bath, in the converter, with carbon.
  • This step is carried out by introducing comminuted coal, preferably anthracite, into the melt at the greatest possible speed. This leads to an extremely violent reaction in which the metal bath is simultaneously deoxidized and carburized. It should be emphasized that, in contrast to conventional deoxidation in the pan using a Kombina tion of coal, ferromanganese, ferrosilicon, aluminum, and the like. the deoxidation product here is exclusively gaseous and therefore cannot lead to inclusions. The large amounts of carbon monoxide formed in this way cause the metal phase to swirl vigorously with the slag phase.
  • the second process step is terminated at an oxygen content of approximately 250-400 ppm 0.
  • the carbon content of the melt is still very low, about 0.04-0.07% C.
  • the added carbon primarily deoxidizes the melt before carburization occurs.
  • the product Cx0 is reduced to the thermodynamic equilibrium value which corresponds to the respective temperature and gas pressure conditions in the metal bath.
  • a "Na 2 O carrier, ie suitable compounds which release Na 2 0 during thermal decomposition, is added, for example by blowing it in together with the carbon.
  • the third process step consists in treating the largely deoxidized and partially carburized bath, taking into account the prevailing conditions with regard to bath temperature, oxygen content, carbon content, i.e. that the product C x 0 at the prevailing temperature is also a determining factor in the subsequent procedure.
  • the procedure is geared towards introducing a melt which is as low in oxygen as possible and whose carbon content is as close as possible to the pan which does not have to be provided with heating units should be below the targeted final concentration.
  • the deoxidation should be carried out as far as possible using carbon, with only carbon monoxide and carbon dioxide being produced.
  • the melt can be further treated with carbon in the converter, specifically until the desired final concentration is reached. If the latter is, for example, about 0.10% C, the corresponding oxygen content is about 200 ppm 0. The rack is then tapped into the pan.
  • This passivity also allows the CxO balance in the converter to be added by adding e.g. Ferromanganese, by blowing into the steel bath, i.e. With the carbon content remaining the same, the oxygen content of the bath can be reduced even further and this without rephosphorization. Solid deoxidation products do occur, but due to the still high steel temperature and the much larger bath diameter: bath height ratio compared to a ladle, these deoxidation products do not lead to inclusions in the finished steel, but are completely eliminated from the melt and absorbed into the slag.
  • e.g. Ferromanganese e.g. Ferromanganese
  • the melt pretreated in this way shows particularly good behavior if it is treated in the pan with a deoxidizing and at the same time desulfurizing agent, preferably metallic calcium and synthetic slags.
  • a deoxidizing and at the same time desulfurizing agent preferably metallic calcium and synthetic slags.
  • desulfurizing agent preferably metallic calcium and synthetic slags.
  • the method according to the invention is aimed at the production of both semi-calmed and fully calmed steels.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
EP86116948A 1985-12-23 1986-12-05 Procédé de fabrication d'acier de haute qualité Withdrawn EP0226912A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
LU86225A LU86225A1 (de) 1985-12-23 1985-12-23 Verfahren zum herstellen von hochwertigem stahl
LU86225 1985-12-23

Publications (2)

Publication Number Publication Date
EP0226912A2 true EP0226912A2 (fr) 1987-07-01
EP0226912A3 EP0226912A3 (fr) 1989-04-26

Family

ID=19730608

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86116948A Withdrawn EP0226912A3 (fr) 1985-12-23 1986-12-05 Procédé de fabrication d'acier de haute qualité

Country Status (6)

Country Link
EP (1) EP0226912A3 (fr)
JP (1) JPS62158811A (fr)
AU (1) AU590801B2 (fr)
BR (1) BR8605894A (fr)
CA (1) CA1288954C (fr)
LU (1) LU86225A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3805410A1 (fr) * 2019-10-11 2021-04-14 SMS Group GmbH Procédé de déphosphoration d'acier fondu pendant le processus d'affinage

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3702243A (en) * 1969-04-15 1972-11-07 Nat Steel Corp Method of preparing deoxidized steel
AU6823981A (en) * 1980-03-21 1981-10-15 Nippon Steel Corporation Multi-stage steel making
LU84168A1 (de) * 1982-05-25 1984-03-07 Arbed Verfahren zum aufkohlen von metallschmelzen
LU85363A1 (fr) * 1984-05-15 1986-01-29 Arbed Dispositif d'adaptation pour tuyere d'acceleration de particules solides

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3805410A1 (fr) * 2019-10-11 2021-04-14 SMS Group GmbH Procédé de déphosphoration d'acier fondu pendant le processus d'affinage

Also Published As

Publication number Publication date
EP0226912A3 (fr) 1989-04-26
JPS62158811A (ja) 1987-07-14
AU6432586A (en) 1987-06-25
AU590801B2 (en) 1989-11-16
BR8605894A (pt) 1987-08-25
CA1288954C (fr) 1991-09-17
LU86225A1 (de) 1987-07-24

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Inventor name: SCHLEIMER, FRANCOIS