US3402757A - Method for continuous casting of steel through a closed gas filled chamber - Google Patents

Method for continuous casting of steel through a closed gas filled chamber Download PDF

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Publication number
US3402757A
US3402757A US508895A US50889565A US3402757A US 3402757 A US3402757 A US 3402757A US 508895 A US508895 A US 508895A US 50889565 A US50889565 A US 50889565A US 3402757 A US3402757 A US 3402757A
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US
United States
Prior art keywords
mould
chamber
gas
tundish
metal
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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
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US508895A
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English (en)
Inventor
Iain M D Halliday
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United Steel Companies Ltd
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United Steel Companies Ltd
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Publication date
Application filed by United Steel Companies Ltd filed Critical United Steel Companies Ltd
Priority to US703496A priority Critical patent/US3482621A/en
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Publication of US3402757A publication Critical patent/US3402757A/en
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/106—Shielding the molten jet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal

Definitions

  • ABSTRACT OF THE DISCLOSURE A method for continuous casting of steel through a gas filled chamber obtains a strand substantially free from oxide formed during pouring and from pin holes Without the use of aluminum.
  • the closed chamber is purged with a reducing or inert gas before starting the cast and is then filled with the gas.
  • An increase in pressure in the closed chamber as the casting proceeds is reduced by permitting the gas to escape at a greater rate than it enters, and reducing gas is passed through the chamber at such a rate that oxygen concentration in the chamber is not greater than 250 parts per million while maintaining the pressure in the chamber substantially constant.
  • This invention relates to improvements in the continuous casting of steel.
  • the metal is commonly poured into a tundish from a ladle and runs from the tundish into an open-ended mould.
  • oxidation of the stream which it is desirable to avoid.
  • This tendency shows itself particularly with chromium-containing steels, aluminium-stabilised steels and other steels containing alloying elements which have a high affinity for oxygen.
  • carbon and low-alloy steels are cast, there is not so much oxidation but there is still a strong tendency for minute pinholes to form at the surface of the cast metal or immediately below the surface.
  • the mechanism of pinhole formation is not known.
  • the formation of pinholes can, however, be greatly reduced or virtually eliminated by feeding aluminium wire into the metal stream as this enters the mould, but this is of little effect in eliminating oxidation and it is undesirable to make any aluminium additions whatever to some steels.
  • steps comprise purging the closed chamber with a reducing gas such as propane or butane or with an inert gas such as argon or nitrogen before the start of a cast; permitting metal to flow through the chamber to the mould while the chamber is substantially filled with the reducing or inert gas; as the mould becomes filled with metal with a consequent tendency to substantial increase in the gas pressure in the closed chamber, reducing this pressure, advantageously substantially to atmospheric pressure, by permitting gas to escape at a greater rate than it enters; and as the casting proceeds passing reducing gas through the chamber at a rate such as to ensure that the oxygen concentration in the chamber is not greater than 250 parts per million while maintaining the pressure in the chamber substantially constant.
  • a reducing gas such as propane or butane or with an inert gas such as argon or nitrogen
  • the important feature is the low concentration of oxygen, and preferably this is maintained at less than parts per million, better still at less than 50 parts per million, and if possible at no more than 20 parts per million.
  • oxygen tends to be introduced into the chamber with the molten metal, and minor leakages may occur during casting; it is therefore necessary to maintain a continuous flow of reducing gas through the chamber throughout the cast. It is of course also necessary first to purge the chamber.
  • the choice of the gas used depends to some extent upon the nature of the steel that is being cast.
  • propane gas or other reducing gas or gas mixtures is normally preferred, as it is also for steels containing easily oxidised alloy elements such as aluminium, but not prone to hydrogen embrittlement.
  • an inert gas such as argon or nitrogen may be used.
  • nitrogen is generally preferred on the grounds of cost, but since commercial nitrogen contains about 200 parts per million of oxygen the concentration of oxygen in the closed chamber may be up to 250 parts per million.
  • the gas that flows through the closed chamber during the casting may be a mixture of an inert gas such as nitrogen and a reducing gas such as propane or other reducing gas in a concentration such that the sum of the hydrogen and water vapour contents does not amount to more than 5,000 parts per million by volume. Again a mixture of nitrogen and a small proportion of carbon monoxide, say up to 5%, may be used.
  • the pressure in the closed chamber must be allowed to fall or at least must not be allowed to rise appreciably above atmospheric. This can be done by increasing the opening of an outlet valve or opening an additional vent valve. It is highly desirable that during the casting the rate of flow of the metal should be substantially constant, and accordingly the pressure in the closed chamber must be maintained substantially constant, since if it varies it will affect the rate of flow.
  • the stroke is normally small, but of course the reciprocation causes the volume of the closed chamber to vary cyclically with consequential variation of the pressure throughout in the same way.
  • the figure is a diagrammatic sectional elevation view of a tundish and mold connected by a closed chamber [for practicing the method of this invention.
  • the closed chamber may take various forms and in designing it account must be taken of the reciprocation of the mould.
  • One simple design is shown diagrammatically in the figure of the accompanying drawings.
  • a tundish 1 with a nozzle 2 let into its base carries a fitting 3 on its underside.
  • the mould is shown at 4, and a fitting 5 is united to the top of it in air-tight fashion.
  • the fittings 3 and 5 are interconnected by a ring 6 of flexible material such as asbestos fabric impregnated with rubber to render it impermeable to gas.
  • the edges of this rings are tightly sealed in the fittings 3 and 5.
  • the flexible ring 6 may be made of thin sheet metal resistant to the heat to which it is subjected.
  • the chamber thus formed within the fittings 3 and S and the ring 6 has a gas inlet 7 to which a valve-controlled pipe for the supply of gas is connected, a gas outlet 8, and a valve-controlled vent 9.
  • a silica window through which the metal stream may be observed.
  • a long length of pipe 1-1 which may be from A2 to 1 /2 inch in diameter conveys away the efiluent gas from the chamber.
  • the length of this pipe 11 should be sufiicient to ensure that the increase in volume when the mould makes a down stroke cannot result in atmospheric oxygen being sucked into the closed chamber.
  • This increase in volume during a mould downstroke is compensated for to some extent by the supply of gas to the chamber, but at high reciprocation rates it is still necessary to provide some length of pipe '11.
  • a valve is included in the pipe .11 to aid control of the gas pressure 'within the enclosure.
  • metal poured into the tundish from a ladle, to flow through the nozzle 2 is of such a design as to produce a rod-like stream.
  • the chamber is purged with gas supplied through the inlet 7. This gas passes out not only through the outlet 8 and pipe 11, but also through the nozzle 2.
  • the metal flows from the tundish through the nozzle 2 as a rod-like stream through the closed chamber into the mould, the base of which is initially closed by a dummy bar.
  • the pressure in the chamber begins to rise, and the vent 9 is opened.
  • the dummy bar is lowered so that the strand begins to form and is continuously withdrawn, and this vent 9 is closed again.
  • the gas outlet from the closed chamber, or the additional vent if one is provided, may be closed under automatic control after being opened at the start of a cast.
  • the valve in the outlet or in the pipe attached to .4 the outlet may be moved to a set postion in response to a signal derived from the level of the metal in the mould, or the additional vent may be closed by such a signal.
  • the signal may be given, for example, by a detector of the gamma ray type.
  • the gas pressure in the closed chamber. duringthe casting may be maintained substantially constant under automatic control in that a valve in the gas inlet, or preferably in the gas outlet, may be controllediby a signal given by the pressure in the chamber and smoothed to prevent the pulsations caused by the reciprocation of the mould from having any effect.
  • a method of obtaining a strand substantially free from oxide formed during the pouring and from pinholes which comprises the steps of purging the closed chamber with a reducing or inert gas before the start of a cast; permitting metal to flow through the chamber to the mold while the chamber is substantially filled with the reducing or inert gas; as the mold becomes filled with metal with a consequent tendency to substantial increase in the gas pressure in the closed chamber, reducing this pressure to a pressure insuflicient to hinder the downward flow of metal by permitting gas to escape at a greater rate than it enters; maintaining the pressure of the gas in the closed chamber substantially constant during the casting so as not to affect the rate of metal flow, and as the casting proceeds passing reducing gas through the chamber at a rate such as to ensure that the oxygen concentration in the chamber is not greater than 250 parts per million while maintaining the pressure in the chamber substantially constant.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Continuous Casting (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
US508895A 1964-11-24 1965-11-22 Method for continuous casting of steel through a closed gas filled chamber Expired - Lifetime US3402757A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US703496A US3482621A (en) 1965-11-22 1967-11-15 Apparatus for continuous casting of steel utilizing a closed chamber between a tundish and a reciprocatable mold

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB47823/64A GB1086094A (en) 1964-11-24 1964-11-24 Methods of and apparatus for use in the continuous casting of steel

Publications (1)

Publication Number Publication Date
US3402757A true US3402757A (en) 1968-09-24

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ID=10446366

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US508895A Expired - Lifetime US3402757A (en) 1964-11-24 1965-11-22 Method for continuous casting of steel through a closed gas filled chamber

Country Status (9)

Country Link
US (1) US3402757A (enrdf_load_stackoverflow)
JP (1) JPS5133850B1 (enrdf_load_stackoverflow)
BE (1) BE672790A (enrdf_load_stackoverflow)
DE (1) DE1483667C3 (enrdf_load_stackoverflow)
ES (2) ES319923A1 (enrdf_load_stackoverflow)
FR (1) FR1454774A (enrdf_load_stackoverflow)
GB (1) GB1086094A (enrdf_load_stackoverflow)
NL (1) NL6515220A (enrdf_load_stackoverflow)
SE (1) SE324636B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3515201A (en) * 1967-11-14 1970-06-02 Amsted Ind Inc Method of casting
US3523684A (en) * 1968-05-31 1970-08-11 United States Steel Corp Vacuum vessel with inlet closure and provision for sealing engagement with teeming ladle
US3689048A (en) * 1971-03-05 1972-09-05 Air Liquide Treatment of molten metal by injection of gas
US3811490A (en) * 1971-03-16 1974-05-21 British Steel Corp Continuous casting of rimming steel
US3833050A (en) * 1968-06-17 1974-09-03 V Kashuba Installation for the continuous casting of non-ferrous metals in a protective gas atmosphere
US3840062A (en) * 1968-07-18 1974-10-08 M Kenney Continuous steel casting method
DE2834746A1 (de) * 1978-08-08 1980-02-21 Hamburger Stahlwerke Gmbh Abschirmvorrichtung fuer einen giessstrahl aus fluessigem metall
US5067552A (en) * 1989-07-26 1991-11-26 Ltv Steel Company, Inc. Shrouding for top pouring of ingots
CN107255193A (zh) * 2017-06-22 2017-10-17 扬中市第蝶阀厂有限公司 一种便于拆卸组装的吹氩接头

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2067117A1 (en) * 1969-11-07 1971-08-20 Ural Z Tyazhelogo Admitting gas into the fluid tight upper part of an ingot mould
DE2607735A1 (de) * 1976-02-23 1977-08-25 Mannesmann Ag Verfahren und einrichtung zur verhinderung der reoxydation des giessstrahles und zur chemischen beeinflussung von metallschmelzen
US4084799A (en) * 1976-08-30 1978-04-18 Georgetown Steel Corporation Shrouding apparatus
DE2919880C2 (de) * 1979-05-17 1983-10-13 Didier-Werke Ag, 6200 Wiesbaden Feuerfestes Gießrohr zwischen Gießpfanne und Zwischenbehältern von Stranggießanlagen
DE2929500C2 (de) * 1979-07-20 1983-03-17 Hamburger Stahlwerke Gmbh, 2103 Hamburg Abschirmvorrichtung für einen Gießstrahl aus flüssigem Metall
FR3032282B1 (fr) 2015-02-03 2018-09-14 Francois Duret Dispositif de visualisation de l'interieur d'une bouche

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2825104A (en) * 1954-03-16 1958-03-04 Askania Regulator Co Method and apparatus for controlling gravity liquid flow, and for continuous metal billet casting
US2889596A (en) * 1957-02-26 1959-06-09 British Iron Steel Research Casting of metals
US3125440A (en) * 1960-12-27 1964-03-17 Tlbr b
US3268958A (en) * 1963-12-19 1966-08-30 Midvale Heppenstall Company Slow pouring and casting system for ferrous and other metals
US3310850A (en) * 1963-12-13 1967-03-28 Rheinstahl Huettenwerke Ag Method and apparatus for degassing and casting metals in a vacuum

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2825104A (en) * 1954-03-16 1958-03-04 Askania Regulator Co Method and apparatus for controlling gravity liquid flow, and for continuous metal billet casting
US2889596A (en) * 1957-02-26 1959-06-09 British Iron Steel Research Casting of metals
US3125440A (en) * 1960-12-27 1964-03-17 Tlbr b
US3310850A (en) * 1963-12-13 1967-03-28 Rheinstahl Huettenwerke Ag Method and apparatus for degassing and casting metals in a vacuum
US3268958A (en) * 1963-12-19 1966-08-30 Midvale Heppenstall Company Slow pouring and casting system for ferrous and other metals

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3515201A (en) * 1967-11-14 1970-06-02 Amsted Ind Inc Method of casting
US3523684A (en) * 1968-05-31 1970-08-11 United States Steel Corp Vacuum vessel with inlet closure and provision for sealing engagement with teeming ladle
US3833050A (en) * 1968-06-17 1974-09-03 V Kashuba Installation for the continuous casting of non-ferrous metals in a protective gas atmosphere
US3840062A (en) * 1968-07-18 1974-10-08 M Kenney Continuous steel casting method
US3689048A (en) * 1971-03-05 1972-09-05 Air Liquide Treatment of molten metal by injection of gas
US3811490A (en) * 1971-03-16 1974-05-21 British Steel Corp Continuous casting of rimming steel
DE2834746A1 (de) * 1978-08-08 1980-02-21 Hamburger Stahlwerke Gmbh Abschirmvorrichtung fuer einen giessstrahl aus fluessigem metall
US5067552A (en) * 1989-07-26 1991-11-26 Ltv Steel Company, Inc. Shrouding for top pouring of ingots
CN107255193A (zh) * 2017-06-22 2017-10-17 扬中市第蝶阀厂有限公司 一种便于拆卸组装的吹氩接头
CN107255193B (zh) * 2017-06-22 2019-07-16 扬中市第一蝶阀厂有限公司 一种便于拆卸组装的吹氩接头

Also Published As

Publication number Publication date
SE324636B (enrdf_load_stackoverflow) 1970-06-08
FR1454774A (fr) 1966-10-07
BE672790A (enrdf_load_stackoverflow) 1966-05-24
DE1483667B2 (de) 1974-11-28
GB1086094A (en) 1967-10-04
ES319923A1 (es) 1966-09-01
ES327425A1 (es) 1967-03-16
JPS5133850B1 (enrdf_load_stackoverflow) 1976-09-22
DE1483667C3 (de) 1975-07-10
NL6515220A (enrdf_load_stackoverflow) 1966-05-25
DE1483667A1 (de) 1969-03-06

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