EP0274290A1 - Stahlgussverfahren mit Schutz des Stahlbades durch Kohlendioxydschnee - Google Patents

Stahlgussverfahren mit Schutz des Stahlbades durch Kohlendioxydschnee Download PDF

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Publication number
EP0274290A1
EP0274290A1 EP87402629A EP87402629A EP0274290A1 EP 0274290 A1 EP0274290 A1 EP 0274290A1 EP 87402629 A EP87402629 A EP 87402629A EP 87402629 A EP87402629 A EP 87402629A EP 0274290 A1 EP0274290 A1 EP 0274290A1
Authority
EP
European Patent Office
Prior art keywords
liquid
distributor
snow
argon
liquid metal
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.)
Granted
Application number
EP87402629A
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English (en)
French (fr)
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EP0274290B1 (de
Inventor
Jean Foulard
Raymond Borasci
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.)
Carboxyque Francaise SA
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Carboxyque Francaise SA
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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 Carboxyque Francaise SA, Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Carboxyque Francaise SA
Priority to AT87402629T priority Critical patent/ATE53519T1/de
Publication of EP0274290A1 publication Critical patent/EP0274290A1/de
Application granted granted Critical
Publication of EP0274290B1 publication Critical patent/EP0274290B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/08—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like for bottom pouring

Definitions

  • the present invention relates to a method for casting steel from a first container into a second container in which protection against oxidation and / or nitriding of the liquid metal is provided. It relates more particularly to a continuous steel casting process in which successively: - pour the liquid steel from a converter or an electric oven into a pocket, - the liquid steel is poured from the ladle into a distributor, - The liquid steel from the distributor is poured into at least one continuous casting mold.
  • liquid metal is in contact with the atmosphere.
  • the nitriding and / or oxidation phenomenon mentioned above lasts from 45 seconds to approximately 4 minutes depending on the size and shape of the distributor.
  • the metal poured into the distributor before immersion of the nozzle is thus more or less strongly oxidized and / or nitrided and the steel billets or ingots formed from this metal do not have the desired metallurgical qualities.
  • said protection against oxidation and / or nitriding of the liquid metal is carried out by injection of carbon dioxide snow and / or liquid argon into the distributor, the injection being carried out in two successive steps: a first step of purging the distributor, taking place before the start of the pouring of the liquid metal, during which carbon dioxide snow and / or liquid argon are injected at a purge rate such as snow or l liquid argon reaches at least partially the bottom of the distributor in which they transform at least patiently into gas, so as to gradually expel the air present in said distributor, this step being completed when the oxygen concentration in the vicinity of the zone corresponding to foot of liquid metal spray at the start of casting is less than about 0.5%, a second step of maintaining the atmosphere around the jet foot, starting when the liquid metal begins to flow in the distributor, during which carbon dioxide snow and / or liquid argon are injected at a rate d '' maintenance, lower than the purge flow, such as the presence of this snow, and / or
  • the second step ends as soon as the lower end of the nozzle is substantially immersed in the liquid metal, the surface of the bath liquid metal in the distributor then being covered with a means of protection against oxidation and / or nitriding, known per se.
  • the maintenance flow will be at most equal to about 50% of the purge flow.
  • the method is characterized in that, before pouring the liquid steel from the converter or the electric furnace into the ladle, a quantity of carbon dioxide snow is injected into it, or sufficient liquid argon to purge said pocket: this quantity of dry ice is preferably between 0.2 and 5 kg per tonne of metal poured, while the flow of liquid argon is greater than 60 liters / min and preferably greater than or equal to 80 liters / min.
  • the duration of this purge is determined by measuring the acceptable residual oxygen concentration at the bottom of the bag. A usual duration is of the order of 45 seconds.
  • the method according to the invention applies to the casting of a jet of liquid steel from a first container into a second container, the casting jet and / or the surface of the bath.
  • liquid metal from the second container being protected against oxidation and / or nitriding by carbon dioxide, in the form of snow, or liquid argon injected in particular as has been explained above, in two successive stages.
  • carbon dioxide snow is used, while designating both carbon dioxide snow and liquid argon.
  • the liquid metal may be subjected to oxidation and / or nitriding.
  • the jet of liquid metal can be oxidized and / or nitrided from the start of the pouring of the electric oven into the ladle. It is therefore generally desirable to provide inerting of the liquid metal at the level of the pocket.
  • the distributor 7 is provided with orifices 8 and 9 allowing the pouring of the liquid metal into the ingot molds 10 and 11.
  • the jet of liquid metal is also, at this location, subjected to the action of the surrounding amosphere, causing oxidation and / or nitriding. This problem was solved by the Applicant by a method as disclosed in European Patent Application No. 213 042.
  • FIG. 2 a view in partial section of a distributor 7 above which has been placed.
  • a bag 4 provided with a nozzle 12.
  • Means 13, 14, 15 are provided for injecting carbon dioxide snow or liquid argon: the reservoir 13 of liquid carbon dioxide (or liquid argon) is connected to the lance 15 by means of a valve 14 (and a nozzle not shown) through which the expansion of the liquid carbon dioxide takes place in the form of snow which is projected into the area 20 of the distributor.
  • the argon remains in the liquid state when passing through the valve 14.
  • the latter essentially comprises a side wall 25 and a bottom wall 16 into which flow orifice openings 8.
  • a small wall 17 is placed opposite the wall 25 relative to the pouring orifice 8 while a baffle 18 is placed in the upper part of the distributor, but slightly offset from the wall, and further from the orifice 8 than said wall 17.
  • the nozzle 12 of the pocket 4 is arranged in the example of the embodiment of FIG. 2, between the two low walls 18 (one of which is not shown in the figure) so that said nozzle is in an area confined by said low walls 17 on the one hand, and said baffles 18 on the other hand. In the example illustrated in this FIG.
  • the lower end of the nozzle 12 is located at a distance D2 from the bottom of the distributor 16, greater than the height D1 of the wall 17, but less than the distance D3 separating the lower part of the baffle 18 of the bottom 16 of said distributor 6.
  • the end 21 of the lance 15 is preferably placed at a distance from the bottom 16 of the distributor, such that this distance is close to the distance D3, in order to allow better penetration of the snow to the bottom of the distributor when injecting it.
  • the distance D2 can be less than D1.
  • the first step of the process consists in purging the distributor of the air present therein. For this, we inject with the lance 15, the end of which is placed as described above, a large quantity of carbon dioxide snow, sufficient so that under the casting conditions (cold or hot distributor before the start carbon dioxide snow is deposited at least partially at the bottom of the distributor, in area 20, located around the lower part of the nozzle 12 and extending to the wall 17.
  • the end of the purge operation triggers the ladle to flow into the distributor. It is indeed very important that the liquid metal flows as soon as this purge flow ends in the distributor because, if it is otherwise, there is a relatively rapid rise in the oxygen concentration, within 1 about one minute. It will therefore be possible, in certain cases, to maintain this high purge flow for a few moments after having started the casting operation in the distributor, or to repeat the purging operation in the event of incidents, at the outlet of the bag, it happens.
  • the carbon dioxide snow present in the zone 20 sublimes quickly but a thickness of snow is maintained by injection of carbon dioxide snow by the lance 15, according to a second flow, or flow maintenance, lower than the purge flow.
  • This flow rate must however be sufficient for snow to cover the liquid metal during the progressive filling of the distributor, including when this liquid metal reaches a level greater than the height D1 of the wall and then spreads quickly throughout the distributor.
  • This holding flow in the form of a constant or substantially regularly decreasing flow, is maintained until the lower end 22 of the nozzle 12 is substantially immersed in the bath of liquid steel.
  • substantially is meant an immersion such that, taking into account the boiling and turbulence usual in this kind of casting, the lower end 22 always remains inside the liquid metal.
  • the injection of carbon dioxide in the form of snow is generally stopped on the surface of the liquid metal and the surface of the metal is covered with a protective powder or any other well-known means of l '' skilled person to limit the oxidation and / or nitriding of molten steel.
  • a protective powder any other well-known means of l '' skilled person to limit the oxidation and / or nitriding of molten steel.
  • Figure 3 is shown an alternative implementation of the method according to the invention in a distributor without a wall.
  • This confinement device 36 comprises a substantially cylindrical envelope 39 provided with a plurality of openings 37, 38 of height d4 such that the surface of the openings allows the liquid metal to flow into the distributor at a flow rate corresponding to that of the metal. 32 through the nozzle 33, in order to avoid an overflow of the metal above the walls 39 of the device 36.
  • This cylindrical device 36 made of metal (consumable), of refractory material (not consumable) or possibly of thick cardboard (which consumes slowly) is fixed by the flanges 40, 41, for example on the walls of the distributor 30.
  • the dry ice is injected, preferably symmetrically on either side of the nozzle 33, by the lances 34, 35.
  • the level of liquid metal rises progressively in the distributor until the nozzle is immersed in the liquid metal, continuous casting is then generally carried out at a flow rate equal to the flow of liquid metal through the nozzle.
  • this diameter is limited by the width of the distributor, as well as by the consumption of snow during the casting operation.
  • These openings are preferably located in the longitudinal part of the distributor, that is to say promoting a flow parallel to the walls thereof.
  • Figure 4 is shown in 4A a schematic sectional view of another embodiment of the invention, while in 4B is shown a top view.
  • the same elements as those in FIG. 3 have the same references.
  • the distributor 30 is in the present case, a narrow distributor (of small width) but of great length.
  • the protection device is limited to two side walls 50, 51 substantially matching the shapes of the distributor, of height d6 greater, as previously, at distance d7 from the lower base of the nozzle to the bottom of the distributor.
  • Each wall has openings 56, 57 in its lower part, arranged so that they allow the flow of liquid metal in the longitudinal direction of the distributor. In FIG. 4A, these openings are placed in the lower corners of the wall 50 (and of the wall 51 - not shown in the figure).
  • Each wall 50, 51 is held by two flanges 52, 53, respectively 54.55, whose lower ends are integral with the corresponding wall and whose upper ends are wound around the corresponding side walls of the distributor 30.
  • the lances are oriented so that the carbon dioxide snow jets, according to the flow rates corresponding to the invention, preferably come into contact with the metal between the nozzle and the walls 50, 51, near the jet base and substantially in the vertical zone of the wall 50, 51 not provided with openings (56, 57), in order to improve the confinement, in particular at the start of casting.
  • the distance between the walls 50, 51 follows substantially the same rules as those defined for determining the diameter of the device 36 in FIG.
  • the distance between the walls 50, 51 must remain reaisonnable so that the device fulfills its confinement function.
  • This distance can, for example, be of the same order of magnitude as the width of said walls 50, 51.
  • Example 1 The procedure is as in Example 1 but using liquid argon instead of carbon dioxide snow.
  • the injection times are the same for the purge and hold rates respectively.
  • the duration of the purging step can be slightly reduced compared to that of Example 1, the liquid argon generating the desired inerting more quickly. This duration can be between 20 and 90 seconds.
  • the flow of liquid argon during the purging step is between 15 liters / min and 30 liters / min and preferably 20 liters / min, for a preferential duration of 45 seconds, from 4 liters to 10 liters per minute and from preferably 6 liters / min during the holding step, the duration of which is at least equal to that of the casting.
  • liquid argon makes it possible to slightly decrease the oxidation of the metal compared to the use of dry ice, with which the results are however excellent.
EP87402629A 1986-11-26 1987-11-23 Stahlgussverfahren mit Schutz des Stahlbades durch Kohlendioxydschnee Expired - Lifetime EP0274290B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87402629T ATE53519T1 (de) 1986-11-26 1987-11-23 Stahlgussverfahren mit schutz des stahlbades durch kohlendioxydschnee.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8616475 1986-11-26
FR8616475A FR2607039B1 (fr) 1986-11-26 1986-11-26 Procede de coulee d'acier comportant un inertage du bain d'acier par de l'anhydride carbonique sous forme de neige

Publications (2)

Publication Number Publication Date
EP0274290A1 true EP0274290A1 (de) 1988-07-13
EP0274290B1 EP0274290B1 (de) 1990-06-13

Family

ID=9341234

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87402629A Expired - Lifetime EP0274290B1 (de) 1986-11-26 1987-11-23 Stahlgussverfahren mit Schutz des Stahlbades durch Kohlendioxydschnee

Country Status (10)

Country Link
US (1) US4781122A (de)
EP (1) EP0274290B1 (de)
JP (1) JPS63252650A (de)
AT (1) ATE53519T1 (de)
AU (1) AU598610B2 (de)
CA (1) CA1330159C (de)
DE (1) DE3763153D1 (de)
ES (1) ES2016643B3 (de)
FR (1) FR2607039B1 (de)
ZA (1) ZA878848B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0383184A1 (de) * 1989-02-14 1990-08-22 INTRACON Handelsgesellschaft für Industriebedarf mbH Verfahren zur Reduzierung von Staubemission und freiem Luftzutritt im Abstichbereich eines Hochofens
US5343491A (en) * 1991-11-28 1994-08-30 Carbagas And Von Roll Ag Method of suppressing dust and fumes during electric steel production
EP0639650A1 (de) * 1993-08-18 1995-02-22 The Commonwealth Industrial Gases Limited Vorrichtung zum Ausbringen von Kohlendioxidschnee
AU667640B2 (en) * 1993-08-18 1996-03-28 Commonwealth Industrial Gases Limited, The CO2 snow discharge apparatus

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2623890B1 (fr) * 1987-11-26 1990-03-30 Air Liquide Lance a neige carbonique pour la metallurgie
US6460742B1 (en) * 1989-02-14 2002-10-08 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for reducing fume emissions during molten metal transfer
US5004495A (en) * 1990-02-05 1991-04-02 Labate M D Method for producing ultra clean steel
IT1257114B (it) * 1992-09-29 1996-01-05 Weber Srl Procedimento per l'ottenimento di masselli reocolati, in particolare adatti a venire utilizzati per la produzione di pressocolati ad alte prestazioni meccaniche.
US6228187B1 (en) 1998-08-19 2001-05-08 Air Liquide America Corp. Apparatus and methods for generating an artificial atmosphere for the heat treating of materials
US6491863B2 (en) 2000-12-12 2002-12-10 L'air Liquide-Societe' Anonyme A' Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes George Claude Method and apparatus for efficient utilization of a cryogen for inert cover in metals melting furnaces
DE102011008894A1 (de) * 2011-01-19 2012-07-19 Air Liquide Deutschland Gmbh Verfahren und Düse zur Unterdrückung einer Entwicklung von eisenhaltigem Dampf
US8932385B2 (en) 2011-10-26 2015-01-13 Air Liquide Industrial U.S. Lp Apparatus and method for metal surface inertion by backfilling
CN113941692A (zh) * 2021-09-14 2022-01-18 包头钢铁（集团）有限责任公司 一种利用二氧化碳预制中间包保护性气氛的方法
CN113953468A (zh) * 2021-09-14 2022-01-21 包头钢铁（集团）有限责任公司 一种利用钢包预加干冰防止出钢过程钢液吸氮的方法

Citations (5)

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Publication number Priority date Publication date Assignee Title
DE2040504A1 (de) * 1970-08-14 1972-02-17 Basf Ag Verfahren zur Verbesserung der Qualitaet von metallischen Gussbloecken
LU70560A1 (de) * 1973-07-24 1974-11-28
EP0154585A2 (de) * 1984-02-24 1985-09-11 Canadian Liquid Air Ltd Air Liquide Canada Ltee Verfahren zum Giessen eines flüssigen Metalles
EP0196242A1 (de) * 1985-02-21 1986-10-01 Canadian Liquid Air Ltd Air Liquide Canada Ltee Verfahren zum Schützen eines Stahlgiessstrahls
EP0196952A2 (de) * 1985-04-01 1986-10-08 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Verfahren zur Herstellung beruhigten Stahls mit niedrigem Stickstoffgehalt

Family Cites Families (6)

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Publication number Priority date Publication date Assignee Title
FR2392746A2 (fr) * 1977-06-01 1978-12-29 Air Liquide Procede de coulee de metal
CH628547A5 (de) * 1978-06-30 1982-03-15 Fischer Ag Georg Formgussverfahren und vorrichtung zum vergiessen von metallischen formgussstuecken in einer form.
JPS57181320A (en) * 1981-04-28 1982-11-08 Nippon Steel Corp Nitrogen absorption preventing method of molten steel
FR2523005A1 (fr) * 1982-03-08 1983-09-16 Air Liquide Procede et installation de coulee d'un metal non ferreux en lingotiere
JPS58154453A (ja) * 1982-03-10 1983-09-13 Daido Steel Co Ltd 溶湯注入方法
JPS591055A (ja) * 1982-06-26 1984-01-06 Kawasaki Steel Corp 連鋳タンデイツシユへの溶鋼無酸化注入開始法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2040504A1 (de) * 1970-08-14 1972-02-17 Basf Ag Verfahren zur Verbesserung der Qualitaet von metallischen Gussbloecken
LU70560A1 (de) * 1973-07-24 1974-11-28
EP0154585A2 (de) * 1984-02-24 1985-09-11 Canadian Liquid Air Ltd Air Liquide Canada Ltee Verfahren zum Giessen eines flüssigen Metalles
EP0196242A1 (de) * 1985-02-21 1986-10-01 Canadian Liquid Air Ltd Air Liquide Canada Ltee Verfahren zum Schützen eines Stahlgiessstrahls
EP0196952A2 (de) * 1985-04-01 1986-10-08 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Verfahren zur Herstellung beruhigten Stahls mit niedrigem Stickstoffgehalt

Non-Patent Citations (1)

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Title
PATENT ABSTRACTS OF JAPAN, vol. 8, no. 83 (M-290)[1520], 17 avril 1984; & JP-A-59 001 055 (KAWASAKI SEITETSU K.K.) 06-01-1984 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0383184A1 (de) * 1989-02-14 1990-08-22 INTRACON Handelsgesellschaft für Industriebedarf mbH Verfahren zur Reduzierung von Staubemission und freiem Luftzutritt im Abstichbereich eines Hochofens
US5683652A (en) * 1989-02-14 1997-11-04 L'air Liquide S.A. Process for reducing dust emissions of a blast furnace
US5343491A (en) * 1991-11-28 1994-08-30 Carbagas And Von Roll Ag Method of suppressing dust and fumes during electric steel production
EP0639650A1 (de) * 1993-08-18 1995-02-22 The Commonwealth Industrial Gases Limited Vorrichtung zum Ausbringen von Kohlendioxidschnee
AU667640B2 (en) * 1993-08-18 1996-03-28 Commonwealth Industrial Gases Limited, The CO2 snow discharge apparatus
US5538184A (en) * 1993-08-18 1996-07-23 The Commonwealth Industrial Gases Limited CO2 snow discharge apparatus

Also Published As

Publication number Publication date
US4781122A (en) 1988-11-01
FR2607039B1 (fr) 1989-03-31
JPS63252650A (ja) 1988-10-19
CA1330159C (fr) 1994-06-14
EP0274290B1 (de) 1990-06-13
ES2016643B3 (es) 1990-11-16
FR2607039A1 (fr) 1988-05-27
ATE53519T1 (de) 1990-06-15
DE3763153D1 (de) 1990-07-19
ZA878848B (en) 1988-05-26
AU8181587A (en) 1988-06-02
AU598610B2 (en) 1990-06-28

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