EP0325242A2 - Verfahren zum Behandeln von Stahl im Vakuum - Google Patents

Verfahren zum Behandeln von Stahl im Vakuum Download PDF

Info

Publication number
EP0325242A2
EP0325242A2 EP89100866A EP89100866A EP0325242A2 EP 0325242 A2 EP0325242 A2 EP 0325242A2 EP 89100866 A EP89100866 A EP 89100866A EP 89100866 A EP89100866 A EP 89100866A EP 0325242 A2 EP0325242 A2 EP 0325242A2
Authority
EP
European Patent Office
Prior art keywords
molten steel
gas
ladle
vacuum vessel
gases containing
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Withdrawn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
EP89100866A
Other languages
English (en)
French (fr)
Other versions
EP0325242A3 (de
Inventor
Toshio C/O Nkk Corporation Ishii
Yutaka c/o NKK Corporation Okubo
Shuzo c/o NKK Corporation Fukuda
Yoshihiko c/o NKK Corporation Kawai
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.)
JFE Engineering Corp
Original Assignee
NKK Corp
Nippon Kokan Ltd
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 NKK Corp, Nippon Kokan Ltd filed Critical NKK Corp
Publication of EP0325242A2 publication Critical patent/EP0325242A2/de
Publication of EP0325242A3 publication Critical patent/EP0325242A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10—Handling in a vacuum

Definitions

  • the present invention relates to a method for refining molten steel in a vacuum, and more particularly to a method for degassing molten steel.
  • a large amount of gas components is contained in molten steel produced in a steel-making furnace such as converter and the like which smelts and refines steel.
  • various vacuum processing methods wherein molten steel is degassed in a vacuum.
  • RH vacuum degassing method molten steel is degassed in such a manner as described below.
  • a ladle is filled up with molten steel to be processed.
  • Two immersion nozzles arranged at the lower portion of a vacuum vessel are immersed in the molten steel from the upper side of the ladle.
  • Inert gas is blown from the middle of one immersion nozzle to have the molten steel in the ladle circulated through the immersion nozzles inside the vacuum vessel. In this way, the molten steel is degassed in the vacuum vessel.
  • Requirements for components of steel for a special use are more severe than those of molten steel processed with RH vacuum degassing method. Therefore, it is necessary to use other methods so as to process molten steel for a special use.
  • a total amount of oxygen in the molten steel needs to be decreased.
  • the total amount of oxygen in the molten steel can barely be decreased to approximately 10 ppm by use of RH vacuum degassing method. Therefore, the RH vacuum degassing method cannot be applied to steel which requires a total amount of oxygen of less than 10 ppm.
  • the present invention provides a method for refining molten steel in a vacuum comprising: an immersion process, wherein two immersion nozzles arranged at the lower portion of a vacuum vessel are immersed in molten steel in a ladle, said two immersion nozzles are a rising tube and a sinking tube; a first degassing process, wherein said molten steel is degassed by keeping said vacuum vessel evacuated, having said molten steel circulated between said ladle and said vacuum vessel being kept evacuated by injecting gases containing at least an inert gas from the middle of said rising tube; and blowing in said molten steel gases containing at least gas soluble in said molten steel.
  • a further method comprising: an immersion process, wherein two immersion nozzles are immersed in molten steel in a ladle, said immersion nozzles are a rising tube and a sinking tube; a dissolving process, wherein gases are dissolved in said molten steel by blowing in said molten steel gases containing at least gas soluble in said molten steel from a gas blow-in opening arranged in said ladle; a first degassing process, wherein said molten steel is degassed by keeping said vacuum vessel evacuated, having said molten steel circulated between said ladle and said vacuum vessel by injecting gases containing at least an inert gas from the middle of said rising tube in said molten steel, and blowing gases containing at least gas soluble in said molten steel from a gas blow-in opening arranged in said ladle; and a second degassing process, wherein said molten steel is degassed by keeping said vacuum vessel evacuated, stopping a gas blowing-in from said gas blow-
  • a method for refining molten steel in a vacuum of the present invention comprises an immersion process, wherein immersion nozzles are immersed in molten steel, a dissolving process, wherein gases are dissolved in said molten steel, a first degassing process and a second degassing process.
  • Two immersion nozzles arranged at the lower portion of vacuum vessel 4 are immersed in molten steel in a ladle.
  • One of the two immersion nozzles is rising tube 5 and the other sinking tube 6.
  • Fig. 1 is a sectional view schematically showing a dissolving process, wherein gases are dissolved in molten steel, according to the present invention.
  • Molten steel 2 inside ladle 1 is pressurized by its static pressure. Gases containing at least gas soluble in molten steel are blown in molten steel 2 through gas blow-in opening 3 arranged at the bottom of ladle 1. It is, of course, possible to blow a mixed gas consisting of gas soluble in said molten steel and an inert gas in said molten steel. Molten steel 2 is bubbled by said mixed gas. Together with bubbling of said molten steel, a large amount of gas soluble in said molten steel dissolves in said molten steel.
  • Gases can be simultaneously blown in said molten steel through gas blow-in opening 7 arranged in rising tube 5 of vacuum vessel 4.
  • the amount of gases dissolved in said molten steel is expected to be quickly increased.
  • a part of inclusions in molten steel 2 is trapped by bubbled gas and rises to the surface of said molten steel.
  • a pressure to said molten steel is decreased.
  • the gases having been dissolved in said molten steel convert to fine bubbles. Fine inclusions in said molten steel are trapped by produced gas bubbles and rise to the surface of said molten steel­.
  • Hydrogen gas, nitrogen gas and hydrocarbon gas as gases soluble in the molten steel are used out of a mixed gas blown in the molten steel.
  • Ar gas and He gas are used as an inert gas. Only gases soluble in the molten steel can be used instead of the mixed gas.
  • gases were blown in the molten steel from gas blow-in opening 3 arranged at the bottom of ladle 1, but ways of a gas blow-in are not limited to this. Gases can be blown in the lower portion of the molten steel in ladle 1.
  • Gas blow-in opening 3, however, is desired to be arranged in the bottom wall of ladle 1 just under rising tube.
  • a large amount of gas can be blown in the molten steel with the use of an immersion lance before an immersion nozzle is immersed in the molten steel.
  • Said immersion lance is immersed from the surface of the molten steel into the molten steel.
  • Fig. 2 is a sectional view schemtically showing a first degassing process of the present invention.
  • Vacuum vessel 4 is kept evacuated.
  • An inert gas is injected from gas blow-in opening 7 arranged in the middle of rising tube 5.
  • molten steel is made to circulate between ladle 1 and vacuum vessel 4.
  • Gases including at least gas soluble in the molten steel are blown in molten steel 2 from gas blow-in opening 3 of ladle 1.
  • Molten steel 2 is bubbled by the gases blown in. Together with bubbling, the gas soluble in the molten steel dissolves in the molten steel.
  • the molten steel is degassed. With the rise of the molten steel toward the surface of the molten steel in vacuum vessel 4, the gas dissolved in the molten steel converts to bubbles. The gas components having been dissolved in the molten steel in the dissolving process and having not appeared near the surface of the molten steel also appear in the form of bubbles. Fine inclusions contained in the molten steel are trapped by the produced gas bubbles and rise to the surface of the molten steel in vacuum vessel 4. A part of the inclusions contained in molten steel 2 are trapped by bubbled inert gas and rises to the surface of the molten steel in vacuum vessel 4.
  • An inert gas was used in this Preferred Embodiment as gas which was injected from the gas blow-in opening arranged in the middle of rising tube 5.
  • the gases to be used are not limited to the inert gas.
  • a mixed gas of an inert gas and gas soluble in the molten steel can be used. In case the mixed gas is used severely, fine inclusions are expected to be removed because the gas is dissolved in the molten steel and fine gas bubbles are produced under decreased pressure.
  • Ar gas and He gas can be used as an inert gas.
  • the gas blown in molten steel 2 from gas blow-in opening 2 of ladle 1 can be either a mixed gas consisting of gas soluble in the molten steel and an inert gas or only gas soluble in the molten steel.
  • Fig. 3 is a sectional view schematically showing a second degassing process of the present invention.
  • Vacuum vessel 4 is kept evacuated.
  • An inert gas is injected in vacuum vessel 4 from gas blow-in opening 7 arranged in the middle of rising tube 5 tomake molten steel circulate between ladle 1 and vacuum vessel 4.
  • Gas blow-in from gas blow-in opening 3 of ladle 1 is stopped. Since the atmospheric pressure in vacuum vessel 4 is decreased to 2 to 3 Torr, the molten steel is degassed. Gas components, which have been dissolved in the molten steel in the first degassing process and have not been able to be removed, are removed. In this Preferred Embodiment, an inert gas was used.
  • the gases to be used are not confined to the inert gas.
  • a permissible concentration of final gas components soluble in molten steel is high, a mixed gas of an inert gas and gas soluble in molten steel can be used.
  • the amount of N in the molten steel increases, but the molten steel is easily processed. Therefore, selection of the methods as mentioned above varies dependent on speicies of steel to be used and equipment which is owened.
  • a mixed gas consisting of 40% Ar gas and 60% H2 gas was blown in said molten steel from gas blow-in opening 7 of rising tube 5 and from gas blow-in opening 3 of ladle 1 respectively at a rate of 180 Nm3/hr and at a rate of 60 Nm3/hr.
  • gas blowing-in from gas blow-in opening 3 of ladle 1 was stopped and, at the same time, 100% Ar gas was blown in the molten steel from gas blow-­in opening 7 of rising tube 5 at a rate of 180 Nm3/hr for 15 minutes.
  • a change of a total amount of oxygen in the molten steel relative to a processing time is indicated in Fig. 4.
  • the total amount of oxygen in the molten steel decreased to 5 ppm in processing of the molten steel for 35 minutes.
  • the amount of hydrogen in the molten steel after having been processed could be decreased to 2 ppm or less.
  • molten steel 250 tons of molten steel were processed with the use of the method (c). Firstly, a top-blow lance was immersed in the molten steel in a ladle and N2 gas was blown in the molten steel at a rate of 180 Nm3/hr for 30 minutes. Subsequently, immersion nozzles were immersed in the molten steel. Vacuum vessel 4 was kept evacuated, and a mixed gas consisting of 60% Ar gas and 40% N2 was blown through gas blow-in opening 7 of rising tube 5 and through gas blow-in opening 3 of ladle 1 respectively at 120 Nm3/hr and at 60 Nm3/hr for 35 minutes. The total amount of oxygen in the molten steel was decreased to approximately 5 ppm by 35 minutes processing of the molten steel. The amount of nitrogen in the molten steel after having been processed was decreased to approximately 90 ppm.
  • molten steel 250 tons of molten steel were processed by use of the method (e). Firstly, a top-blow lance was immersed in the molten steel in a ladle and N2 was blown in the molten steel at 180 Nm3/hr for 30 minutes. Subsequently, immersion nozzles were immersed in the molten steel. Vacuum vessel 4 was kept evacuated and Ar gas was blown through gas blow-in opening 7 of rising tube 5 at 120 Nm3/hr for 35 minutes. The total amount of oxygen in the molten steel was decreased to approximately 6 ppm by 35 minutes processing of the molten steel. The amount of nitrogen in the molten steel after having been processed was decreased to approximately 35 ppm.
  • molten steel 250 tons of molten steel were processed by use of the method (b).
  • a mixed gas consisting of 20% Ar gas and 80% N2 gas was blown in the molten steel through gas blow-in opening 7 of rising tube 5 and N2 gas through gas blow-in opening 3 of ladle 1 respectively at 120 Nm3/hr and at 60 Nm3/hr.
  • blowing-in of N2 gas through gas blow-in opening 3 of ladle 1 was stopped, and, at the same time, 100% Ar gas blown in the molten steel through gas blow-in opening 7 of rising tube 5 at 120 Nm3/hr for 15 minutes.
  • the total amount of oxygen in the molten steel was decreased to approximately 6 ppm by 35 minutes processing of the molten steel.
  • the amount of nitrogen in the molten steel was decreased to approximately 40 ppm.
  • molten steel 250 tons of molten steel was processed by use of the method (a). Firstly, a top-blow lance was immersed in the molten steel in a ladle, and N2 gas was blown in the molten steel at 180 Nm3/hr for half an hour. Then, immersion nozzles were immersed in the molten steel. Vacuum vessel 4 was kept evacuated. For the first 20 minutes, a mixed gas consisting of 20% Ar gas and 80% N2 gas was blown in vacuum vessel 4 through gas blow-­in opening 7 of rising tube 5 and N2 gas through gas blow-in opening 3 of ladle 1 respectively at 120 Nm3/hr and at 60 Nm3/hr.
  • a mixed gas consisting of 20% Ar gas and 80% N2 gas was blown in vacuum vessel 4 through gas blow-­in opening 7 of rising tube 5 and N2 gas through gas blow-in opening 3 of ladle 1 respectively at 120 Nm3/hr and at 60 Nm3/hr.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Continuous Casting (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
EP89100866A 1988-01-21 1989-01-19 Verfahren zum Behandeln von Stahl im Vakuum Withdrawn EP0325242A3 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP63009675A JPH01188619A (ja) 1988-01-21 1988-01-21 Ｒｈ真空脱ガス法
JP9675/88 1988-01-21
JP1031105A JPH02211974A (ja) 1988-01-21 1989-02-13 溶融金属の減圧清浄化方法

Publications (2)

Publication Number Publication Date
EP0325242A2 true EP0325242A2 (de) 1989-07-26
EP0325242A3 EP0325242A3 (de) 1990-02-14

Family

ID=39689269

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89100866A Withdrawn EP0325242A3 (de) 1988-01-21 1989-01-19 Verfahren zum Behandeln von Stahl im Vakuum

Country Status (6)

Country Link
EP (1) EP0325242A3 (de)
JP (2) JPH01188619A (de)
KR (1) KR930005067B1 (de)
AU (1) AU601893B2 (de)
BR (1) BR8900249A (de)
CA (1) CA1338397C (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0461415A1 (de) * 1990-05-17 1991-12-18 Kawasaki Steel Corporation Verfahren zum Herstellen kohlenstoffarmer Stähle
US5077255A (en) * 1986-09-09 1991-12-31 Exxon Chemical Patents Inc. New supported polymerization catalyst
WO2000034533A2 (de) * 1998-12-04 2000-06-15 Vai Technometal Gmbh Verfahren zur entstickung von stahlschmelzen
FR2809745A1 (fr) * 2000-06-05 2001-12-07 Sanyo Special Steel Co Ltd Acier haute proprete et son procede de production
GB2406580A (en) * 2000-06-05 2005-04-06 Sanyo Special Steel Co Ltd High-cleanliness steel and processes for producing the same
GB2410503A (en) * 2000-06-05 2005-08-03 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
EP1568790A1 (de) * 2004-02-24 2005-08-31 Paul Wurth S.A. Vorrichtung zur metallurgischen Behandlung von Metalschmelze in einer Pfanne
CN109922905A (zh) * 2016-11-09 2019-06-21 株式会社Posco 铸造设备和使用该铸造设备的铸造方法
CN113957203A (zh) * 2021-12-21 2022-01-21 太原科技大学 一种多功能非中心对称真空精炼设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102296159B (zh) * 2010-06-25 2013-05-01 鞍钢股份有限公司 一种插入管堵塞的处理方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB954214A (en) * 1959-08-14 1964-04-02 Heraeus Gmbh W C Improvements in or relating to the vacuum degassing of metals
DE1222090B (de) * 1960-09-09 1966-08-04 Heraeus Gmbh W C Verfahren zum Entgasen von Stahlschmelzen
US3320053A (en) * 1964-09-25 1967-05-16 Bethlehem Steel Corp Method of injecting gases into steel melts
JPS57194206A (en) * 1981-05-26 1982-11-29 Kawasaki Steel Corp Production of molten extra low carbon steel
JPS57200514A (en) * 1981-06-03 1982-12-08 Nippon Kokan Kk <Nkk> Method for degassing molten steel
JPS5837112A (ja) * 1981-08-29 1983-03-04 Kawasaki Steel Corp 溶鋼の真空精練法
JPS60184619A (ja) * 1984-02-29 1985-09-20 Sumitomo Metal Ind Ltd 低窒素鋼の製造方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU601602B2 (en) * 1987-06-29 1990-09-13 Kawasaki Steel Corporation Method and apparatus for degassing molten metal utilizing RH method
AU605949B2 (en) * 1987-12-25 1991-01-24 Nkk Corporation Method for cleaning molten metal and apparatus therefor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB954214A (en) * 1959-08-14 1964-04-02 Heraeus Gmbh W C Improvements in or relating to the vacuum degassing of metals
DE1222090B (de) * 1960-09-09 1966-08-04 Heraeus Gmbh W C Verfahren zum Entgasen von Stahlschmelzen
US3320053A (en) * 1964-09-25 1967-05-16 Bethlehem Steel Corp Method of injecting gases into steel melts
JPS57194206A (en) * 1981-05-26 1982-11-29 Kawasaki Steel Corp Production of molten extra low carbon steel
JPS57200514A (en) * 1981-06-03 1982-12-08 Nippon Kokan Kk <Nkk> Method for degassing molten steel
JPS5837112A (ja) * 1981-08-29 1983-03-04 Kawasaki Steel Corp 溶鋼の真空精練法
JPS60184619A (ja) * 1984-02-29 1985-09-20 Sumitomo Metal Ind Ltd 低窒素鋼の製造方法

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, vol. 10, no.31 (C-327)[2088], 6th February 1986; & JP-A-60 184 619 (SUMITOMO KINZOKU KOGYO K.K.) 20-09-1985 *
PATENT ABSTRACTS OF JAPAN, vol. 7, no. 118 (C-167)[1263], 21st May 1983; & JP-A-58 37 112 (KAWASAKI SEITETSU K.K.) 04-03-1983 *
PATENT ABSTRACTS OF JAPAN, vol. 7, no. 43 (C-152)[1188], 19th February 1983; & JP-A-57 194 206 (KAWASAKI SEITETSU K.K.) 29-11-1982 *
PATENT ABSTRACTS OF JAPAN, vol. 7, no. 53 (C-154)[1198], 3rd March 1983; & JP-A-57 200 514 (NIPPON KOKAN K.K.) 08-12-1982 *

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5077255A (en) * 1986-09-09 1991-12-31 Exxon Chemical Patents Inc. New supported polymerization catalyst
US5183867A (en) * 1986-09-09 1993-02-02 Exxon Chemical Patents Inc. Polymerization process using a new supported polymerization catalyst
EP0461415A1 (de) * 1990-05-17 1991-12-18 Kawasaki Steel Corporation Verfahren zum Herstellen kohlenstoffarmer Stähle
WO2000034533A2 (de) * 1998-12-04 2000-06-15 Vai Technometal Gmbh Verfahren zur entstickung von stahlschmelzen
WO2000034533A3 (de) * 1998-12-04 2002-10-03 Vai Technometal Gmbh Verfahren zur entstickung von stahlschmelzen
WO2001094648A3 (en) * 2000-06-05 2002-08-08 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
GB2410503A (en) * 2000-06-05 2005-08-03 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
FR2812660A1 (fr) * 2000-06-05 2002-02-08 Sanyo Special Steel Co Ltd Acier haute proprete et son procede de production
FR2812661A1 (fr) * 2000-06-05 2002-02-08 Sanyo Special Steel Co Ltd Acier haute proprete et son procede de production
FR2812662A1 (fr) * 2000-06-05 2002-02-08 Sanyo Special Steel Co Ltd Acier haute proprete et son procede de production
WO2001094648A2 (en) * 2000-06-05 2001-12-13 Sanyo Special Steel Co., Ltd. High-cleanliness steel and process for producing the same
FR2809745A1 (fr) * 2000-06-05 2001-12-07 Sanyo Special Steel Co Ltd Acier haute proprete et son procede de production
GB2381537A (en) * 2000-06-05 2003-05-07 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
GB2406580A (en) * 2000-06-05 2005-04-06 Sanyo Special Steel Co Ltd High-cleanliness steel and processes for producing the same
FR2812663A1 (fr) * 2000-06-05 2002-02-08 Sanyo Special Steel Co Ltd Acier haute proprete et son procede de fabrication
US7396378B2 (en) 2000-06-05 2008-07-08 Sanyo Special Steel Co., Ltd. Process for producing a high cleanliness steel
GB2381537B (en) * 2000-06-05 2005-09-14 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
GB2406580B (en) * 2000-06-05 2005-09-07 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
GB2410503B (en) * 2000-06-05 2005-09-07 Sanyo Special Steel Co Ltd High-cleanliness steel and process for producing the same
WO2005080612A1 (fr) * 2004-02-24 2005-09-01 Sms Mevac Gmbh Dispositif pour le traitement de metal liquide en poche
EP1568790A1 (de) * 2004-02-24 2005-08-31 Paul Wurth S.A. Vorrichtung zur metallurgischen Behandlung von Metalschmelze in einer Pfanne
CN109922905A (zh) * 2016-11-09 2019-06-21 株式会社Posco 铸造设备和使用该铸造设备的铸造方法
CN113957203A (zh) * 2021-12-21 2022-01-21 太原科技大学 一种多功能非中心对称真空精炼设备

Also Published As

Publication number Publication date
AU601893B2 (en) 1990-09-20
CA1338397C (en) 1996-06-18
EP0325242A3 (de) 1990-02-14
KR930005067B1 (ko) 1993-06-15
JPH02211974A (ja) 1990-08-23
KR890012009A (ko) 1989-08-23
AU2848289A (en) 1989-08-10
BR8900249A (pt) 1989-09-19
JPH01188619A (ja) 1989-07-27

Similar Documents

Publication Publication Date Title
EP0325242A2 (de) Verfahren zum Behandeln von Stahl im Vakuum
EP0707080B1 (de) Verfahren zur herstellung von stahlschmelze mit niedrigem kohlenstoffgehalt durch vakuumentgasung und -entkohlung
EP0203695A1 (de) Verfahren zum Frischen einer Metallschmelze mit Berücksichtigung des Stickstoffgehaltes
GB2057509A (en) Steel making in top-blown converter
CA1205638A (en) Production of ultra low carbon steel by the basic oxygen process
JPH11315315A (ja) 液体金属を減圧下で処理するための冶金反応装置
EP1757706B1 (de) Verfeinerungsverfahren für Stahlschmelze
JP2000212641A (ja) 溶鋼の高速真空精錬方法
KR100328061B1 (ko) 대기압하에서의극저탄소용강의제조방법
KR100743211B1 (ko) 헬륨 분사에 의한 동시 교반을 이용한 용융 금속의 진공 처리 방법
KR100226917B1 (ko) 투피스캔용 고청정강의 제조방법
JPH05287356A (ja) 取鍋精錬方法
JP2003171716A (ja) 真空脱ガス槽付着地金の除去方法
JP2000160220A (ja) スラグ・フォーミングの抑制方法
JPH08302419A (ja) 溶鋼の精錬方法
JPH05320739A (ja) 真空精錬方法
JPH0610029A (ja) 極低炭素鋼の製造方法
JPS5644711A (en) Decarbonization method of molten steel under reduced pressure
JPH0610028A (ja) 極低炭素鋼の製造方法
JP2718096B2 (ja) 溶融金属の減圧清浄化方法
Ishii et al. Method for Refining Molten Steel in a Vacuum
JP3071445B2 (ja) 溶鋼の真空精錬における窒素の低減方法
JPH0512410B2 (de)
JPH05271747A (ja) 真空脱ガス処理による溶鋼の精錬方法
JPH0741836A (ja) 低真空精錬による低窒素鋼の溶製方法

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19890119

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB IT

RIN1 Information on inventor provided before grant (corrected)

Inventor name: FUKUDA, SHUZO C/O PATENTS & LICENSE & QUALITY

Inventor name: ISHII, TOSHIO C/O PATENTS & LICENSE & QUALITY

Inventor name: KAWAI, YOSHIHIKO C/O PATENTS & LICENSE & QUALITY

Inventor name: OKUBO, YUTAKA C/O PATENTS & LICENSE & QUALITY

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB IT

17Q First examination report despatched

Effective date: 19920515

APCB Communication from the board of appeal sent

Free format text: ORIGINAL CODE: EPIDOS OBAPE

APCB Communication from the board of appeal sent

Free format text: ORIGINAL CODE: EPIDOS OBAPE

APAB Appeal dossier modified

Free format text: ORIGINAL CODE: EPIDOS NOAPE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19980926

APAF Appeal reference modified

Free format text: ORIGINAL CODE: EPIDOSCREFNE