EP1268863A1 - Vacuum treatment of cast metal with simultaneous helium-injection stirring - Google Patents

Vacuum treatment of cast metal with simultaneous helium-injection stirring

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Publication number
EP1268863A1
EP1268863A1 EP01919572A EP01919572A EP1268863A1 EP 1268863 A1 EP1268863 A1 EP 1268863A1 EP 01919572 A EP01919572 A EP 01919572A EP 01919572 A EP01919572 A EP 01919572A EP 1268863 A1 EP1268863 A1 EP 1268863A1
Authority
EP
European Patent Office
Prior art keywords
treatment
steel
helium
metal
ladle
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
EP01919572A
Other languages
German (de)
French (fr)
Other versions
EP1268863B1 (en
Inventor
François Stouvenot
Marc Burty
Jean-François DOMGIN
Pascal Gardin
Dominique Viale
Raymond Reitz
Frédéric LECLERCQ
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USINOR SA
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USINOR SA
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Publication date
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Publication of EP1268863A1 publication Critical patent/EP1268863A1/en
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Publication of EP1268863B1 publication Critical patent/EP1268863B1/en
Anticipated expiration legal-status Critical
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D27/00—Stirring devices for molten material
    • 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/072—Treatment with gases
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D27/00—Stirring devices for molten material
    • F27D2027/002—Gas stirring

Definitions

  • the invention relates to a method of vacuum treatment of a molten metal in liquid form, such as steel for example.
  • a molten metal in liquid form such as steel for example.
  • the effervescent steel must generally undergo various complementary metallurgical operations which are carried out in a bag equipped with a vacuum installation. These operations generally consist of a deoxidation of the liquid metal then in its nuance and at temperature before the solidification of this metal in continuous casting or in an ingot mold.
  • a so-called degassing treatment is carried out, the efficiency of which is greatly improved by placing the atmosphere under vacuum in contact with the liquid metal. .
  • the decarburization of steel occurs by combining oxygen with the carbon dissolved in the metal to form carbon monoxide gas.
  • This decarburization is assisted by stirring of the liquid metal carried out for example, by injection of a neutral gas, argon most often, into the liquid steel from the bottom of the ladle.
  • Efficient stirring is essential for good decarburization, as well as degassing, because the depression created above the bath affects only a weak layer of steel at the top of the bath. It is therefore essential to continuously supply this reaction zone with the steel located below to ensure the desired overall performance. The same goes for dehydrogenation or denitriding treatments.
  • the stirring of the liquid steel however creates an agitation of the surface of the steel covered by the slag.
  • This agitation which is further exacerbated when the bag is placed under vacuum, can cause projections of liquid steel and slag on the walls of the bag, the lid or the tank in which the bag to be treated is placed.
  • the operator In order to limit such projections and to prevent the liquid metal and the supernatant slag from overflowing, the operator must maintain a safety distance between the surface of the liquid steel at rest and the upper rim of the ladle, the distance called guard height. The compliance with this guard height therefore requires limiting the filling of the metallurgical ladle to a value lower than its nominal value
  • the object of the invention is to provide a method for treating larger quantities of liquid metal in a vacuum bag while ensuring the correct course of this treatment.
  • the subject of the invention is a process for the vacuum treatment of a molten metal in liquid form comprising the steps consisting in:
  • the invention may also have the following characteristics - the treatment is a decarburization treatment which is applied to steel,
  • the treated metal is steel which has a carbon content of less than 60 ppm after having been decarburized
  • the treatment is a dehydrogenation treatment which is applied to steel
  • the treatment is a denitriding treatment which is applied to steel
  • the flow of helium injected is greater than or equal to 1.875 Nl / min for 1 ton of molten metal, - the injection of helium is carried out through the wall of the pocket which is provided with gas injectors implanted below the level of liquid metal,
  • the invention consists in coupling the use of helium as a stirring gas with the establishment of a guard height lower than usual practices.
  • the present inventors have in fact found that by using helium as a stirring gas in place of argon or nitrogen, the phenomena of agitation of the surface of the liquid steel are very significantly attenuated, allowing thus reducing the guard height and therefore increasing the filling rate of liquid metal in the bag, resulting in a significant gain in productivity.
  • the vacuum treatment of a molten metal such as steel is carried out by prior filling of a metallurgical ladle until a guard height generally between 0.6 and 1 m is reached, then by placing the bag under vacuum, inside which argon or nitrogen are injected simultaneously to stir the steel.
  • the pocket used in this example is of substantially cylindrical shape with a total height of about 4.4 meters and a maximum capacity of 300 tonnes of steel. By setting the guard height to a value of 0.8 m, one can generally process 240 tonnes per pocket.
  • the operation was carried out using the method according to the invention by carrying out a vacuum treatment of 240 t of liquid steel in a bag similar to that of the example of the prior art which has just been described, while injecting helium, under the same conditions as above.
  • the helium flow rates injected are of the order of 150 Nl / min for each of the porous plugs in the vacuuming phase, ie 1.875 Nl / t / min in all. These flow rates are then increased to 200 Nl / min for each of the plugs when the bag is under a vacuum of 1 mbar or less, ie a total flow of 2.5 Nl / t / min. It is then surprisingly found that the agitation of the surface of the liquid steel is reduced.
  • the treatment can be completed during the available period of time, which makes it possible to obtain a steel conforming to the targeted characteristics.
  • the injection of the gas into liquid metal can be carried out by any type of injector such as, in particular, at least one porous plug inserted in the bottom of the bag, or at least one lance immersed directly in the liquid metal .
  • the process according to the invention is more particularly suited to the implementation of vacuum decarburization treatments of steels, for which it is desired to obtain a final carbon content of less than 60 ppm, but it can be used in any metallurgical process under vacuum requiring stirring and involving compliance with a guard height.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
  • Soy Sauces And Products Related Thereto (AREA)

Abstract

A vacuum treatment of cast metal in liquid form employing the steps of: introducing the cast metal in liquid form into a metallurgic ladle; filling the ladle until a guard height ranging between 0.4 and 0.6 m is reached; and treating the metal while bringing the atmosphere above the ladle under vacuum, and simultaneously stirring the cast metal by injecting helium into the base of the ladle during part of or the whole treatment.

Description

TRAITEMENT SOUS VIDE D ' UN METAL FONDU AVEC BRASSAGE SIMULTANE PAR INJECTION D ' HELIUMVACUUM TREATMENT OF MOLTEN METAL WITH SIMULTANEOUS BREWING BY HELIUM INJECTION
L'invention concerne un procédé de traitement sous vide d'un métal fondu sous forme liquide, tel que de l'acier par exemple. A la sortie du convertisseur, l'acier effervescent doit généralement subir diverses opérations métallurgiques complémentaires que l'on effectue en poche équipée d'une installation sous vide. Ces opérations consistent généralement en une désoxydation du métal liquide puis à sa mise à nuance et à température avant la solidification de ce métal en coulée continue ou en lingotière. Pour certaines applications nécessitant de basses teneurs en gaz dissous (hydrogène et azote) et/ou en carbone, on procède à un traitement dit de dégazage dont l'efficacité est largement améliorée par la mise sous dépression de l'atmosphère en contact du métal liquide.The invention relates to a method of vacuum treatment of a molten metal in liquid form, such as steel for example. At the outlet of the converter, the effervescent steel must generally undergo various complementary metallurgical operations which are carried out in a bag equipped with a vacuum installation. These operations generally consist of a deoxidation of the liquid metal then in its nuance and at temperature before the solidification of this metal in continuous casting or in an ingot mold. For certain applications requiring low contents of dissolved gas (hydrogen and nitrogen) and / or carbon, a so-called degassing treatment is carried out, the efficiency of which is greatly improved by placing the atmosphere under vacuum in contact with the liquid metal. .
Pour le traitement de décarburation par exemple, lorsque les conditions adéquates de composition de l'acier et de pression au dessus du bain sont réunies, la décarburation de l'acier se produit par combinaison de l'oxygène avec le carbone dissous dans le métal pour former du monoxyde de carbone gazeux. Cette décarburation est assistée par un brassage du métal liquide effectué par exemple, par injection d'un gaz neutre, l'argon le plus souvent, dans l'acier liquide depuis le fond de poche.For the decarburization treatment for example, when the adequate conditions of steel composition and pressure above the bath are met, the decarburization of steel occurs by combining oxygen with the carbon dissolved in the metal to form carbon monoxide gas. This decarburization is assisted by stirring of the liquid metal carried out for example, by injection of a neutral gas, argon most often, into the liquid steel from the bottom of the ladle.
Un brassage efficace est indispensable à la bonne réalisation de la décarburation, comme du dégazage, car la dépression créée au dessus du bain n'affecte qu'une faible couche d'acier à la partie supérieure du bain. Il est donc essentiel d'alimenter en permanence cette zone de réaction par l'acier situé en- dessous pour assurer les performances globales souhaitées. Il en va de même pour les traitements de déshydrogénation ou de dénitruration.Efficient stirring is essential for good decarburization, as well as degassing, because the depression created above the bath affects only a weak layer of steel at the top of the bath. It is therefore essential to continuously supply this reaction zone with the steel located below to ensure the desired overall performance. The same goes for dehydrogenation or denitriding treatments.
D'une façon générale, le brassage de l'acier liquide crée cependant une agitation de la surface de l'acier recouvert par le laitier. Cette agitation, encore exacerbée lorsque la poche est mise sous vide, peut provoquer des projections d'acier liquide et de laitier sur les parois de la poche, du couvercle ou de la cuve dans laquelle est placée la poche à traiter. Afin de limiter de telles projections et d'éviter que le métal liquide et le laitier surnageant ne débordent, l'exploitant doit maintenir une distance de sécurité entre la surface de l'acier liquide au repos et le rebord supérieur de la poche, distance appelée hauteur de garde. Le respect de cette hauteur de garde impose donc de limiter le remplissage de la poche métallurgique à une valeur inférieure a sa valeur nominaleIn general, the stirring of the liquid steel however creates an agitation of the surface of the steel covered by the slag. This agitation, which is further exacerbated when the bag is placed under vacuum, can cause projections of liquid steel and slag on the walls of the bag, the lid or the tank in which the bag to be treated is placed. In order to limit such projections and to prevent the liquid metal and the supernatant slag from overflowing, the operator must maintain a safety distance between the surface of the liquid steel at rest and the upper rim of the ladle, the distance called guard height. The compliance with this guard height therefore requires limiting the filling of the metallurgical ladle to a value lower than its nominal value
Sinon, l'opérateur serait contraint de limiter le débit de brassage, voire même de supprimer ce brassage pour limiter l'agitation en surface, ce qui peut conduire directement à un déclassement de l'acier obtenuOtherwise, the operator would be forced to limit the stirring rate, or even eliminate this stirring to limit surface agitation, which can directly lead to derating of the steel obtained
Ainsi, l'invention a pour but de proposer un procédé permettant de traiter en poche sous vide de plus grandes quantités de métal liquide tout en garantissant le déroulement correct de ce traitementThus, the object of the invention is to provide a method for treating larger quantities of liquid metal in a vacuum bag while ensuring the correct course of this treatment.
A cet effet, l'invention a pour objet un procédé de traitement sous vide d'un métal fondu sous forme liquide comprenant les étapes consistant aTo this end, the subject of the invention is a process for the vacuum treatment of a molten metal in liquid form comprising the steps consisting in:
- introduire le métal fondu sous forme liquide dans une poche métallurgique en remplissant ladite poche jusqu'à atteindre une hauteur de garde comprise entre 0,4 et 0,6 m,introducing the molten metal in liquid form into a metallurgical ladle by filling said ladle until reaching a guard height of between 0.4 and 0.6 m,
- traiter le métal tout en mettant l'atmosphère au dessus de ladite poche sous dépression et en procédant simultanément à un brassage du métal fondu par injection d'hélium dans le fond de ladite poche pendant une partie ou la totalité du traitementtreating the metal while placing the atmosphere above said pocket under vacuum and simultaneously mixing the molten metal by injecting helium into the bottom of said pocket during part or all of the treatment
L'invention peut en outre présenter les caractéristiques suivantes - le traitement est un traitement de décarburation que l'on applique a de l'acier,The invention may also have the following characteristics - the treatment is a decarburization treatment which is applied to steel,
- le métal traité est de l'acier qui présente une teneur en carbone inférieure à 60 ppm après avoir été décarburé,the treated metal is steel which has a carbon content of less than 60 ppm after having been decarburized,
- le traitement est un traitement de déshydrogénation que l'on applique à de l'acier,the treatment is a dehydrogenation treatment which is applied to steel,
- le traitement est un traitement de dénitruration que l'on applique à de l'acier,the treatment is a denitriding treatment which is applied to steel,
- le débit d'hélium injecté est supérieur ou égal à 1 ,875 Nl/min pour 1 tonne de métal fondu, - l'injection d'hélium est effectuée au travers de la paroi de la poche qui est pourvue d'injecteurs de gaz implantés en dessous du niveau du métal liquide,- the flow of helium injected is greater than or equal to 1.875 Nl / min for 1 ton of molten metal, - the injection of helium is carried out through the wall of the pocket which is provided with gas injectors implanted below the level of liquid metal,
- l'injection d'hélium est effectuée au travers du fond de la poche qui est pourvue d'injecteurs de gaz dans son fond. Comme on l'aura compris, l'invention consiste à coupler l'utilisation de l'hélium comme gaz de brassage à l'établissement d'une hauteur de garde inférieure aux pratiques habituelles. Les présents inventeurs ont en effet constaté qu'en utilisant comme gaz de brassage l'hélium à la place de l'argon ou de l'azote, les phénomènes d'agitation de la surface de l'acier liquide sont très sensiblement atténués, permettant ainsi de réduire la hauteur de garde et par conséquent d'augmenter le taux de remplissage en métal liquide de la poche, d'où un gain de productivité important.- helium injection is carried out through the bottom of the pocket which has gas injectors at the bottom. As will be understood, the invention consists in coupling the use of helium as a stirring gas with the establishment of a guard height lower than usual practices. The present inventors have in fact found that by using helium as a stirring gas in place of argon or nitrogen, the phenomena of agitation of the surface of the liquid steel are very significantly attenuated, allowing thus reducing the guard height and therefore increasing the filling rate of liquid metal in the bag, resulting in a significant gain in productivity.
Un exemple de procédé de l'art antérieur et un exemple de mise en œuvre de l'invention dans le cas de la décarburation de l'acier liquide en cuve sous vide vont à présent être décrits.An example of a process of the prior art and an example of implementation of the invention in the case of decarburization of liquid steel in a vacuum tank will now be described.
Dans l'art antérieur, le traitement sous vide d'un métal fondu tel que de l'acier, est réalisé par remplissage préalable d'une poche métallurgique jusqu'à atteindre une hauteur de garde généralement comprise entre 0,6 et 1 m, puis par mise sous vide de la poche à l'intérieur de laquelle on procède simultanément à l'injection d'argon ou d'azote pour brasser l'acier.In the prior art, the vacuum treatment of a molten metal such as steel is carried out by prior filling of a metallurgical ladle until a guard height generally between 0.6 and 1 m is reached, then by placing the bag under vacuum, inside which argon or nitrogen are injected simultaneously to stir the steel.
La poche utilisée dans cet exemple est de forme sensiblement cylindrique avec une hauteur totale de 4,4 mètres environ et une contenance maximale de 300 tonnes d'acier. En réglant la hauteur de garde à une valeur de 0,8 m, on peut généralement traiter 240 tonnes par poche. Les injecteurs de gaz utilisés sont constitués de trois bouchons poreux insérés dans le fond de la poche. Ces bouchons poreux sont conçus pour supporter chacun un débit de gaz maximum de 600 Nl/min (1 NI = 1 litre mesuré dans des conditions normales de température et de pression).The pocket used in this example is of substantially cylindrical shape with a total height of about 4.4 meters and a maximum capacity of 300 tonnes of steel. By setting the guard height to a value of 0.8 m, one can generally process 240 tonnes per pocket. The gas injectors used consist of three porous plugs inserted in the bottom of the bag. These porous plugs are designed to each support a maximum gas flow of 600 Nl / min (1 NI = 1 liter measured under normal temperature and pressure conditions).
Lorsque la poche contenant l'acier liquide est placée dans une enceinte que l'on met progressivement sous dépression, il se produit une émission de CO provenant des couches supérieures du métal dans la poche, à un niveau de pression dans l'enceinte correspondant à la pression de CO en équilibre avec les activités en carbone et oxygène dissous dans le métal. Le débit de ces émissions de CO par ébullition spontanée sous l'effet de la dépression est relativement important et conduit à une élévation du niveau de métal en poche et à la formation de projections métalliques. Du fait de cette émission de CO, le débit de brassage doit être limité pour chacun des bouchons poreux, typiquement de 50 à 80 Nl/min, pour une hauteur de garde initiale de 0,8 m, soit un débit total de gaz neutre injecté de 0,625 à 1 Nl/t/min.When the pocket containing the liquid steel is placed in an enclosure which is gradually placed under vacuum, there is an emission of CO coming from the upper layers of the metal in the pocket, at a pressure level in the enclosure corresponding to CO pressure in equilibrium with carbon and dissolved oxygen activities in the metal. The flow of these CO emissions by spontaneous boiling under the effect of depression is relatively large and leads to an increase in the level of metal in the ladle and to the formation of metallic projections. Due to this CO emission, the stirring flow rate must be limited for each porous plug, typically from 50 to 80 Nl / min, for an initial guard height of 0.8 m, i.e. a total flow of injected neutral gas from 0.625 to 1 Nl / rpm .
Lorsque le débit d'émission de CO se réduit, à la suite de la diminution de la teneur en carbone du métal, on procède généralement à une augmentation du débit de gaz de brassage qui intervient en phase dite de bas vide, pour laquelle la pression dans l'enceinte contenant la poche est à une pression inférieure à 10 mbar, typiquement de l'ordre de 1 mbar. Le débit de gaz injecté par élément poreux est typiquement de 200 Nl/min, soit un débit total d'argon ou d'azote injecté dans la poche de 2,5 Nl/min par tonne d'acier.When the CO emission flow is reduced, following the decrease in the carbon content of the metal, there is generally an increase in the flow of stirring gas which occurs in the so-called low vacuum phase, for which the pressure in the enclosure containing the bag is at a pressure of less than 10 mbar, typically of the order of 1 mbar. The flow rate of gas injected per porous element is typically 200 Nl / min, ie a total flow rate of argon or nitrogen injected into the pocket of 2.5 Nl / min per tonne of steel.
Dans ces conditions, le degré d'agitation de la surface de l'acier liquide ainsi que le débit des projections d'acier générées sous l'effet conjugué de l'ébullition du CO et du gaz de brassage reste acceptable tout au long du traitement. Si l'on réduisait la hauteur de garde à une valeur comprise entre 0,4 etUnder these conditions, the degree of agitation of the surface of the liquid steel as well as the flow rate of the steel projections generated under the combined effect of the boiling of the CO and the stirring gas remains acceptable throughout the treatment. . If we reduced the guard height to a value between 0.4 and
0,6 m, en injectant de l'argon ou de l'azote, il serait indispensable de réduire fortement le débit d'injection de gaz neutre à des débits inférieurs à ceux indiqués pour une hauteur de garde standard, ce qui conduirait, à durée de traitement sous vide identique, à une dégradation des performances de décarburation. Dans le cas d'une décarburation d'acier, cela mènerait à un acier insuffisamment décarburé et donc impropre à l'usage visé.0.6 m, by injecting argon or nitrogen, it would be essential to greatly reduce the neutral gas injection rate to rates lower than those indicated for a standard guard height, which would lead to identical vacuum treatment time, degrading decarburization performance. In the case of a decarburization of steel, this would lead to an insufficiently decarburized steel and therefore unsuitable for the intended use.
On a opéré à l'aide du procédé selon l'invention en effectuant un traitement sous vide de 240 t d'acier liquide dans une poche similaire à celle de l'exemple de l'art antérieur qui vient d'être décrit, tout en injectant de l'hélium, dans les mêmes conditions que précédemment. Les débits d'hélium injectés sont de l'ordre de 150 Nl/min pour chacun des bouchons poreux dans la phase de mise sous vide, soit 1 ,875 Nl/t/min en tout. Ces débits sont ensuite augmentés jusqu'à 200 Nl/min pour chacun des bouchons lorsque la poche est sous un vide de 1 mbar ou moins, soit un débit total de 2,5 Nl/t/min. On constate alors de façon surprenante que l'agitation de la surface de l'acier liquide est réduite. Les projections d'acier liquide sur les parois de la poche sont par conséquent également réduites, ce qui permet de remplir la poche jusqu'à laisser une hauteur de garde comprise entre 0,4 et 0,6 m. Ce sont ainsi 20 tonnes d'acier liquide supplémentaires qui peuvent être traitées en une seule opération, avec les mêmes performances métallurgiques et les mêmes conditions de sécurité qu'avec l'injection d'argon ou d'azote, d'où un gain de productivité de l'ordre de 10 %.The operation was carried out using the method according to the invention by carrying out a vacuum treatment of 240 t of liquid steel in a bag similar to that of the example of the prior art which has just been described, while injecting helium, under the same conditions as above. The helium flow rates injected are of the order of 150 Nl / min for each of the porous plugs in the vacuuming phase, ie 1.875 Nl / t / min in all. These flow rates are then increased to 200 Nl / min for each of the plugs when the bag is under a vacuum of 1 mbar or less, ie a total flow of 2.5 Nl / t / min. It is then surprisingly found that the agitation of the surface of the liquid steel is reduced. The projections of liquid steel on the walls of the pocket are therefore also reduced, which makes it possible to fill the pocket until leaving a guard height of between 0.4 and 0.6 m. An additional 20 tonnes of liquid steel can therefore be treated in a single operation, with the same metallurgical performance and the same safety conditions as with the injection of argon or nitrogen, resulting in a productivity gain of around 10%.
En outre, le traitement peut être mené à son terme pendant le laps de temps disponible, ce qui permet d'obtenir un acier conforme aux caractéristiques visées.In addition, the treatment can be completed during the available period of time, which makes it possible to obtain a steel conforming to the targeted characteristics.
Bien entendu, l'injection du gaz dans de métal liquide peut être réalisée par tout type d'injecteur tel que, notamment, au moins un bouchon poreux inséré dans le fond de la poche, ou au moins une lance immergée directement dans le métal liquide.Of course, the injection of the gas into liquid metal can be carried out by any type of injector such as, in particular, at least one porous plug inserted in the bottom of the bag, or at least one lance immersed directly in the liquid metal .
Le procédé selon l'invention est plus particulièrement adapté à la mise en œuvre de traitements de décarburation sous vide d'aciers, pour lesquels on souhaite obtenir une teneur finale en carbone inférieure à 60 ppm, mais il pourra être utilisé dans tout procédé métallurgique sous vide nécessitant un brassage et impliquant le respect d'une hauteur de garde. The process according to the invention is more particularly suited to the implementation of vacuum decarburization treatments of steels, for which it is desired to obtain a final carbon content of less than 60 ppm, but it can be used in any metallurgical process under vacuum requiring stirring and involving compliance with a guard height.

Claims

REVENDICATIONS
1. Procédé de traitement sous vide d'un métal fondu sous forme liquide comprenant les étapes consistant à :1. Process for the vacuum treatment of a molten metal in liquid form comprising the steps consisting in:
- introduire le métal fondu sous forme liquide dans une poche métallurgique en remplissant ladite poche jusqu'à atteindre une hauteur de garde comprise entre 0,4 et 0,6 m,introducing the molten metal in liquid form into a metallurgical ladle by filling said ladle until reaching a guard height of between 0.4 and 0.6 m,
- traiter le métal tout en mettant l'atmosphère au dessus de ladite poche sous dépression et en procédant simultanément à un brassage du métal fondu par injection d'hélium dans le fond de ladite poche pendant une partie ou la totalité du traitement.- Treat the metal while putting the atmosphere above said pocket under vacuum and simultaneously mixing the molten metal by injecting helium into the bottom of said pocket during part or all of the treatment.
2. Procédé selon la revendication 1 , caractérisé en ce que ledit traitement est un traitement de décarburation que l'on applique à de l'acier. 2. Method according to claim 1, characterized in that said treatment is a decarburization treatment which is applied to steel.
3. Procédé selon la revendication 2, caractérisé en ce que l'acier présente une teneur en carbone inférieure à 60 ppm après avoir été décarburé.3. Method according to claim 2, characterized in that the steel has a carbon content of less than 60 ppm after having been decarburized.
4. Procédé selon la revendication 1 , caractérisé en ce que ledit traitement est un traitement de déshydrogénation que l'on applique à de l'acier.4. Method according to claim 1, characterized in that said treatment is a dehydrogenation treatment which is applied to steel.
5. Procédé selon la revendication 1 , caractérisé en ce que ledit traitement est un traitement de dénitruration que l'on applique à de l'acier.5. Method according to claim 1, characterized in that said treatment is a denitriding treatment which is applied to steel.
6. Procédé selon l'une quelconque des revendications 1 à 5, caractérisé en ce que le débit d'hélium injecté est supérieur ou égal à 1 ,875 Nl/min, pour 1 tonne de métal fondu.6. Method according to any one of claims 1 to 5, characterized in that the helium flow injected is greater than or equal to 1.875 Nl / min, for 1 ton of molten metal.
7. Procédé selon l'une quelconque des revendications 1 à 6, caractérisé en ce que l'on effectue ladite injection d'hélium au travers de la paroi de la poche qui est pourvue d'injecteurs de gaz implantés en dessous du niveau du métal liquide.7. Method according to any one of claims 1 to 6, characterized in that said helium injection is carried out through the wall of the pocket which is provided with gas injectors located below the level of the metal liquid.
8. Procédé selon la revendication 7, caractérisé en ce que l'on effectue ladite injection d'hélium au travers du fond de la poche qui est pourvue d'injecteurs de gaz dans son fond. 8. Method according to claim 7, characterized in that said helium injection is carried out through the bottom of the bag which is provided with gas injectors in its bottom.
EP01919572A 2000-03-29 2001-03-27 Vacuum treatment of cast metal with simultaneous helium-injection stirring Expired - Lifetime EP1268863B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0003966A FR2807066B1 (en) 2000-03-29 2000-03-29 PNEUMATIC BREWING PROCESS FOR POUCHED LIQUID METAL
FR0003966 2000-03-29
PCT/FR2001/000918 WO2001073140A1 (en) 2000-03-29 2001-03-27 Vacuum treatment of cast metal with simultaneous helium-injection stirring

Publications (2)

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EP1268863A1 true EP1268863A1 (en) 2003-01-02
EP1268863B1 EP1268863B1 (en) 2003-12-17

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US (1) US6843826B2 (en)
EP (1) EP1268863B1 (en)
JP (1) JP5010086B2 (en)
KR (1) KR100743211B1 (en)
CN (1) CN1253586C (en)
AT (1) ATE256756T1 (en)
AU (1) AU2001246647A1 (en)
BR (1) BR0109628A (en)
CA (1) CA2404633C (en)
DE (1) DE60101564T2 (en)
ES (1) ES2211793T3 (en)
FR (1) FR2807066B1 (en)
MX (1) MXPA02009461A (en)
RU (1) RU2257417C2 (en)
TR (1) TR200301788T3 (en)
WO (1) WO2001073140A1 (en)

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GB0427832D0 (en) * 2004-12-20 2005-01-19 Boc Group Plc Degassing molten metal
CN107401930B (en) * 2017-07-25 2019-04-26 攀钢集团研究院有限公司 Jet stirring system for electro-aluminothermic process vanadium titanium smelting furnace

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB938221A (en) * 1958-12-02 1963-10-02 Finkl & Sons Co Improvements relating to the degassing of molten metals
BE609880A (en) * 1960-11-18
FR2291287A2 (en) * 1974-11-13 1976-06-11 Creusot Loire BLOWING METHOD WITH A VIEW TO OBTAINING VERY LOW CARBON CONTENTS IN CHROME STEELS
US4071356A (en) * 1976-11-24 1978-01-31 Nippon Steel Corporation Method for refining a molten steel in vacuum
JPS5442324A (en) * 1977-09-10 1979-04-04 Nisshin Steel Co Ltd Control procedure of steel making process using mass spectrometer
JPS5952203B2 (en) * 1979-03-22 1984-12-18 住友金属工業株式会社 Manufacturing method of ultra-low carbon steel
FR2473064A1 (en) * 1980-01-02 1981-07-10 Siderurgie Fse Inst Rech PROCESS FOR PNEUMATIC BREWING OF A FUSION METAL BATH
JPS59150009A (en) * 1983-02-12 1984-08-28 Daido Steel Co Ltd Refining method of steel
FR2545393B1 (en) * 1983-05-04 1985-09-06 Air Liquide PROCESS FOR PRODUCING SOLID METAL PARTICLES FROM A METAL BATH
JPS62235416A (en) * 1986-04-04 1987-10-15 Kawasaki Steel Corp Method for refining molten metal
JPH0243315A (en) * 1988-08-01 1990-02-13 Kawasaki Steel Corp Method and device for reflux type degassing treatment of molten steel
JPH02282414A (en) * 1988-10-24 1990-11-20 A Finkl & Sons Co Method and apparatus for treating molten steel
JPH05311229A (en) * 1992-05-06 1993-11-22 Kobe Steel Ltd Ladle degassing treatment apparatus
JPH05311227A (en) * 1992-05-07 1993-11-22 Nippon Steel Corp Reduced pressure-vacuum degassing refining method for molten metal
JPH05339624A (en) * 1992-06-04 1993-12-21 Nippon Steel Corp Smelting method for dead soft steel by circular column type ladle degassing device
JPH06306444A (en) * 1993-04-28 1994-11-01 Kawasaki Steel Corp Method for melting extra low carbon and extra low nitrogen steel in vacuum degassing apparatus
FR2772653B1 (en) * 1997-12-22 2000-01-21 Lorraine Laminage METALLURGICAL REACTOR FOR REDUCED PRESSURE TREATMENT OF A LIQUID METAL

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0173140A1 *

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FR2807066A1 (en) 2001-10-05
EP1268863B1 (en) 2003-12-17
JP5010086B2 (en) 2012-08-29
DE60101564T2 (en) 2004-09-16
DE60101564D1 (en) 2004-01-29
CA2404633C (en) 2009-12-15
FR2807066B1 (en) 2002-10-11
WO2001073140A1 (en) 2001-10-04
KR100743211B1 (en) 2007-07-26
TR200301788T4 (en) 2004-01-21
RU2257417C2 (en) 2005-07-27
JP2003528981A (en) 2003-09-30
MXPA02009461A (en) 2003-09-05
ES2211793T3 (en) 2004-07-16
CN1420938A (en) 2003-05-28
CN1253586C (en) 2006-04-26
US20040035248A1 (en) 2004-02-26
KR20020086728A (en) 2002-11-18
AU2001246647A1 (en) 2001-10-08
TR200301788T3 (en) 2004-01-21
BR0109628A (en) 2003-04-22
US6843826B2 (en) 2005-01-18
ATE256756T1 (en) 2004-01-15
CA2404633A1 (en) 2001-10-04

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