EP0362851B1 - Method for cleaning molten metal - Google Patents

Method for cleaning molten metal Download PDF

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Publication number
EP0362851B1
EP0362851B1 EP89118517A EP89118517A EP0362851B1 EP 0362851 B1 EP0362851 B1 EP 0362851B1 EP 89118517 A EP89118517 A EP 89118517A EP 89118517 A EP89118517 A EP 89118517A EP 0362851 B1 EP0362851 B1 EP 0362851B1
Authority
EP
European Patent Office
Prior art keywords
pressure
molten metal
gas
vessel
molten steel
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.)
Expired - Lifetime
Application number
EP89118517A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0362851A2 (en
EP0362851A3 (en
Inventor
Toshio C/O Patent & License Department Ishii
Shunichi C/O Patent & License Department Sugiyama
Yoshiteru C/O Patent & License Department Kikuchi
Hidetoshi C/O Patent & License Department Matsuno
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
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
Priority claimed from JP63250807A external-priority patent/JPH0742524B2/ja
Priority claimed from JP25080688A external-priority patent/JP2718096B2/ja
Priority claimed from JP1031105A external-priority patent/JPH02211974A/ja
Application filed by NKK Corp filed Critical NKK Corp
Publication of EP0362851A2 publication Critical patent/EP0362851A2/en
Publication of EP0362851A3 publication Critical patent/EP0362851A3/en
Application granted granted Critical
Publication of EP0362851B1 publication Critical patent/EP0362851B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/02—Roasting processes
    • C22B1/04—Blast roasting
    • 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
    • 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
    • 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
    • C21C7/0081—Treating and handling under pressure
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ

Definitions

  • the above-mentioned method is very effective in removal of the inclusions in the molten metal.
  • the molten metal is pressurized at the initial stage of a processing step, some portion of the bubbling gas having once dissolved in the molten metal appears as fine gas bubbles during the reduction of the pressure on the molten metal, but the rest of the gas remains dissolved in the molten metal. Accordingly, one more processing step for degassing the molten metal is required after the above-mentioned processing of the gas has been carried out. Therefore, there have been problems in that degassing capacity and the number of processing steps had to be increased. In addition, a cost for equipment increased because of the use of a pressure vessel.
  • zone A is two-dimensional rectangular coordinates, whose ordinate is P S Torr and whose abscissa is P E Torr.
  • the preferable zone B is two-dimensional rectangular coordinates, whose ordinate is P S Torr and whose abscissa is P E .
  • Example-2 When the molten steel is stirred by blowing inert gas into the molten steel under reduced pressure as in the Example-1, soluble gas is remarkably removed from the molten steel and the amount of nitrogen decreased to the extent enough to be able to be put to practical use inspite of bubbling of the soluble gas in comparison with Control-1 and Control-2 in Table 1.
  • the soluble gas however, is removed during the pressure reduction and, at the same time, the occurrence of fine gas bubbles is also decreased. Accordingly, it is thought that the effect of rising and separation of nonmetallic inclusions decreases with the lapse of time. Therefore, it is intended in Example-2 to keep the effect of the rising and separation of the nonmetallic inclusions by blowing the soluble gas together with the inert gas during the pressure reduction.
  • the molten steel was bubbled by blowing Ar gas as inert gas together with N2 gas from the bottom of the ladle at a rate of 150 Nl/min. Flow of N2 gas was decreased to zero in the last five minutes as shown in Table 2 so as to make the amount of soluble gas as small as possible.
  • Table 2 Time after Pressure Reduction 0 ⁇ 10 10 ⁇ 15 15 ⁇ 20 Amount of Gas Blown into Molten Steel Nl/min Ar 100 30 150 N2 50 120 0
  • referential numeral 22 denotes an exhaust opening for exhausting inside atmosphere which is arranged in a ceiling of the gas tight vessel 2, 21 a gas injection opening arranged in the bottom of the chamber 2a, 23 an exit port for outflow of the molten steel which is arranged in the bottom of the chamber 2b and 24 an inlet for inflow of the molten steel which is arranged in a ceiling of the chamber 2a.
  • Said gas injection opening 21 and said inlet for inflow of the molten steel are arranged so that they can be opened for closed if necessary.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Manufacture And Refinement Of Metals (AREA)
EP89118517A 1988-10-06 1989-10-05 Method for cleaning molten metal Expired - Lifetime EP0362851B1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP250806/88 1988-10-06
JP250807/88 1988-10-06
JP63250807A JPH0742524B2 (ja) 1988-10-06 1988-10-06 溶融金属の清浄化方法
JP25080688A JP2718096B2 (ja) 1988-10-06 1988-10-06 溶融金属の減圧清浄化方法
JP31105/89 1989-02-13
JP1031105A JPH02211974A (ja) 1988-01-21 1989-02-13 溶融金属の減圧清浄化方法

Publications (3)

Publication Number Publication Date
EP0362851A2 EP0362851A2 (en) 1990-04-11
EP0362851A3 EP0362851A3 (en) 1990-06-20
EP0362851B1 true EP0362851B1 (en) 1993-03-31

Family

ID=27287204

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89118517A Expired - Lifetime EP0362851B1 (en) 1988-10-06 1989-10-05 Method for cleaning molten metal

Country Status (6)

Country Link
EP (1) EP0362851B1 (ko)
KR (1) KR920006578B1 (ko)
AU (2) AU4245789A (ko)
BR (1) BR8905068A (ko)
CA (1) CA1339703C (ko)
DE (1) DE68905741T2 (ko)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5004495A (en) * 1990-02-05 1991-04-02 Labate M D Method for producing ultra clean steel

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1582780A (ko) * 1968-01-10 1969-10-10
US3635696A (en) * 1968-05-21 1972-01-18 Finkl & Sons Co Treatment of molten metal using arc heat and vacuum
DE2710577A1 (de) * 1977-03-11 1978-09-14 Thyssen Edelstahlwerke Ag Verfahren zum frischen von stahl
DE3426736A1 (de) * 1984-07-20 1986-01-30 Klöckner CRA Technologie GmbH, 4100 Duisburg Verfahren zur spuelgasbehandlung von metallschmelzen
GB2162604B (en) * 1984-07-30 1988-05-25 Teves Gmbh Alfred Braking pressure generator for a hydraulic brake system
US4780134A (en) * 1986-09-23 1988-10-25 A. Finkl & Sons Co. Simplified method and apparatus for treating molten steel

Also Published As

Publication number Publication date
EP0362851A2 (en) 1990-04-11
KR920006578B1 (ko) 1992-08-10
DE68905741D1 (de) 1993-05-06
KR900006541A (ko) 1990-05-08
DE68905741T2 (de) 1993-09-23
EP0362851A3 (en) 1990-06-20
CA1339703C (en) 1998-03-10
BR8905068A (pt) 1990-05-08
AU1397692A (en) 1992-05-28
AU655245B2 (en) 1994-12-08
AU4245789A (en) 1990-08-16

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