EP0196952A2 - Verfahren zur Herstellung beruhigten Stahls mit niedrigem Stickstoffgehalt - Google Patents

Verfahren zur Herstellung beruhigten Stahls mit niedrigem Stickstoffgehalt Download PDF

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Publication number
EP0196952A2
EP0196952A2 EP86400532A EP86400532A EP0196952A2 EP 0196952 A2 EP0196952 A2 EP 0196952A2 EP 86400532 A EP86400532 A EP 86400532A EP 86400532 A EP86400532 A EP 86400532A EP 0196952 A2 EP0196952 A2 EP 0196952A2
Authority
EP
European Patent Office
Prior art keywords
steel
carbon dioxide
ladle
additives
pocket
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
EP86400532A
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English (en)
French (fr)
Other versions
EP0196952B1 (de
EP0196952A3 (en
Inventor
Jean-Michel Naud
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Publication date
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=9317817&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0196952(A2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to AT86400532T priority Critical patent/ATE56896T1/de
Publication of EP0196952A2 publication Critical patent/EP0196952A2/de
Publication of EP0196952A3 publication Critical patent/EP0196952A3/fr
Application granted granted Critical
Publication of EP0196952B1 publication Critical patent/EP0196952B1/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
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/003—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting by using inert 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing

Definitions

  • the present invention relates to a process for obtaining a calm steel with low nitrogen content by pouring an effervescent steel from a converter into a ladle, in which molten steel located in the ladle is added during of the casting operation, in particular additives for calming this steel such as aluminum, and / or silicon.
  • Certain metals or alloys of metals can in particular, during their development, see their quantity of nitrogen increase if no special precautions are taken. This is the case, for example, of steel when it is poured from a converter into a pocket or more generally a transmitting container into a receiving container. It has been found that the presence of nitrogen in a steel, in the form of interstitial impurities promotes hardening by aging and reduces its resistance. In particular, it is found that a sheet having a too high nitrogen content is poorly resistant to aging and corrosion after deep drawing.
  • the essential principle of this process consists, before any metal casting, in completely replacing the air in the bag, a non-nitriding gas by injecting this gas into said bag and covering this bag of a cover, the two measures, taken separately, not making it possible to achieve the desired goal, that is to say the reduction in the amount of nitrogen absorbed by the steel during this ladle pouring.
  • carbon dioxide is used in the form of blocks of carbon dioxide ice ("dry ice" according to English terminology) deposited in the bottom of the pocket before closing it by the cover.
  • the method according to the invention makes it possible to use carbon dioxide in the form of carbon dioxide snow to protect the surface of the steel bath so as to obtain both a small amount of dissolved oxygen in the steel, after soaking, as well as a small amount of nitrogen, while avoiding the drawbacks mentioned above.
  • the method of obtaining callus steel - ied from effervescent steel according to the invention is characterized in that the effervescent the steel is cast into the bag sufficient to allow the introduction of additives and calmage in that a few moments before the introduction of these calming additives, carbon dioxide is injected in the form of carbon dioxide snow, near the base of the pouring jet and on the surface of the steel bath in the ladle, in sufficient quantity to protect the surface of the molten metal from the surrounding air as soon as the calming additives are introduced into the ladle.
  • the density of the carbon dioxide snow used (density of the solid particles of this carbon dioxide snow) must be less than or equal to 1.1 kg / dm 3 .
  • the carbon dioxide snow which is suitable for implementing the invention is snow produced by an apparatus known as a cyclone.
  • This snow comes from the sudden expansion of liquid carbon dioxide, generally stored at a temperature of - 20 ° C and a pressure of 20 bars directly in the atmosphere, that is to say at ambient temperature and pressure.
  • the snow thus formed is used as is, generally without further treatment.
  • this makes it possible to have the carbon dioxide snow generator near the place of pouring and to inject this snow into the pocket by a supply line connected to the cyclone. Continuous or sequential feeding can thus be easily controlled by the operator who controls the casting of metal.
  • the quantities of dry ice required vary from 0.2 to 5 kg per tonne of metal cast.
  • this method is preferably applied for the protection of the pouring jet between the converter and the ladle but can also be applied for the casting of a first ladle in a second ladle or in a continuous casting distributor, as well as the distributor in the molds, etc ...
  • the effervescent steel 1 is located in the converter 2 under the orifice 3 from which the bag 4 is brought.
  • a predetermined amount of carbon dioxide snow is injected before adding the calming additives such as aluminum or silicon as well as the additives (if necessary) such as silico manganese, ferrovanadium, ferromanganese fuel, ferroneobium, carbon in the form of carburite, etc. well-known additives to give the desired properties and grades to steels.
  • the liquid metal 5 immediately sublimates the carbon dioxide snow present in the zone of the jet foot 6, and in the zone situated above the layer of liquid metal 7, thus creating a layer 8 of carbon dioxide, surmounted by a layer 9 of air.
  • the whole liquid metal 7 and carbon dioxide sheet thus form a piston, as the liquid level rises, which expels the air from the pocket, the jet foot thus being constantly protected.
  • FIG. 2 shows a variant of FIG. 1, in which the carbon dioxide snow is injected into the pocket just before the addition of the calming additives (continuously or sequentially), using a supply 10, on the one hand connected to the reservoir 12 of liquid C0 2 and on the other hand connected to the bag 4 by the expansion valve 11.
  • Snow 14 spreads over all of the liquid metal. For this, a symmetrical supply can be provided at several points.
  • Continuous or sequential feeding using the reservoir 12 makes it possible to generate, by expansion of the liquid C0 2 , approximately 40% solid and 60% gas.
  • the latter dilutes the atmosphere of the ladle and improves the protection of the pouring jet. Furthermore, this gas, heavier than air, heats up in contact with the liquid metal before being entrained towards the surface of said metal, thus avoiding excessive cooling of the metal.
  • FIG. 3 represents a simplified view of implementation of the method according to the invention.
  • a receiving pocket 32 is placed under the converter 30 containing the molten steel 31, this pocket being supported by a carriage 33 moving on the rails 34, 35.
  • a reservoir 36 of carbon dioxide liquid 50 At the same level as these is placed a reservoir 36 of carbon dioxide liquid 50. This reservoir is protected by a firewall 37.
  • the liquid carbon dioxide is sent (by means not shown in the figures) via the pipe 38 to an apparatus 41 for making carbon dioxide snow called carbocyclone, such as those sold by CARDOX.
  • Line 38 ends with two nozzles shown diagrammatically at 39 oriented 180 ° from one another, playing the role of expansion orifices at ambient temperature and pressure of the carbon dioxide stored at approximately -20 ° C. and 20 bars in the tank 36.
  • This expansion in the downward-facing cone 40 causes the appearance of carbon dioxide snow which is stored in the bucket 42 placed on the scale 43.
  • the injection is stopped and the bucket is moved on the pouring floor 51 located at the level of the converter, above the ladle. Through the opening 52 in the floor 51, the snow from the bucket 42 is poured into the pocket 32, a few moments before the addition of the soothing additives.
  • An effervescent steel comprising 1.5% carbon, 10% chromium, 0.09% silicon, 0.08% manganese, 0.012% sulfur and 0.011% carbon is poured from a converter into a 1 ton bag. phosphorus.
  • a sample of the liquid steel is taken from the converter before casting and from the ladle after casting.
  • the renitriding of the casting according to the invention has decreased by 37%.
  • the initial nitrogen concentration in the bag is not the same in the two cases, since it is impossible to have the same initial nitrogen concentrations for two successive mergers carried out under the same conditions.
  • the Applicant has verified that the reduction in renitriding does not depend on the initial nitrogen concentration.
  • Example 2 The operation is carried out under conditions similar to that of Example 1 but with a bag receiving 6 tonnes of effervescent steel comprising from 0.2 to 0.3% of carbon, from 0.6 to 0.7% of manganese and 0.2 to 0.7% silicon.
  • the steel is poured into the pocket up to about a third of its height.
  • Then injected about 5 kg of dry ice (in one or more times until the end of the casting).
  • the steel calming additives are introduced, in a manner known per se.
  • the renitrutation decreased by 40%.
  • Example 3 Under the same conditions as in Example 2, an effervescent steel of the following composition is poured:
  • This table also shows that we can modulate the quantity of dry ice introduced according to the result that we aim to obtain: we will put more dry ice / per tonne if we want to avoid as much as possible re-nitriding, while avoiding reoxidation, while the addition of a small amount of C0 2 / tonne of metal unexpectedly decreases reoxidation, while also reducing renitriding.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Heat Treatment Of Steel (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Continuous Casting (AREA)
EP86400532A 1985-04-01 1986-03-13 Verfahren zur Herstellung beruhigten Stahls mit niedrigem Stickstoffgehalt Expired - Lifetime EP0196952B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86400532T ATE56896T1 (de) 1985-04-01 1986-03-13 Verfahren zur herstellung beruhigten stahls mit niedrigem stickstoffgehalt.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8504909 1985-04-01
FR8504909A FR2579495B1 (fr) 1985-04-01 1985-04-01 Procede de protection d'un jet de coulee de metal

Publications (3)

Publication Number Publication Date
EP0196952A2 true EP0196952A2 (de) 1986-10-08
EP0196952A3 EP0196952A3 (en) 1988-10-26
EP0196952B1 EP0196952B1 (de) 1990-09-26

Family

ID=9317817

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86400532A Expired - Lifetime EP0196952B1 (de) 1985-04-01 1986-03-13 Verfahren zur Herstellung beruhigten Stahls mit niedrigem Stickstoffgehalt

Country Status (11)

Country Link
US (1) US4666511A (de)
EP (1) EP0196952B1 (de)
JP (1) JPS61235507A (de)
AT (1) ATE56896T1 (de)
AU (1) AU586856B2 (de)
BR (1) BR8601411A (de)
CA (1) CA1268044A (de)
DE (1) DE3674446D1 (de)
ES (1) ES8702810A1 (de)
FR (1) FR2579495B1 (de)
ZA (1) ZA862011B (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2607039A1 (fr) * 1986-11-26 1988-05-27 Air Liquide Procede de coulee d'acier comportant un inertage du bain d'acier par de l'anhydride carbonique sous forme de neige
EP0288369A2 (de) * 1987-04-20 1988-10-26 Liquid Air Corporation Verfahren und Einrichtung zum Schutz eines flüssigen Metallstromes

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4657587A (en) * 1985-02-21 1987-04-14 Canadian Liquid Air Ltd./Air Liquide Canada Ltee Molten metal casting
FR2623890B1 (fr) * 1987-11-26 1990-03-30 Air Liquide Lance a neige carbonique pour la metallurgie
DE3904415C1 (de) * 1989-02-14 1990-04-26 Intracon Handelsgesellschaft Fuer Industriebedarf M.B.H., 6200 Wiesbaden, De
DK0544967T3 (da) * 1991-11-28 1995-10-16 Von Roll Ag Fremgangsmåde til at undertrykke støv og røg ved fremstillingen af elektrostål
US5344478A (en) * 1993-08-02 1994-09-06 Air Products And Chemicals, Inc. Vortex dispersing nozzle for liquefied cryogenic inert gases used in blanketing of molten metals exposed to ambient air and method
AU5323498A (en) * 1996-11-08 1998-06-03 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for reducing fume emissions during molten metal transfer
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
DE10038543A1 (de) * 2000-08-03 2002-02-14 Linde Gas Ag Verfahren zum Schützen der Oberfläche einer Magnesiumschmelze
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
DE102006033698A1 (de) * 2006-07-20 2008-01-24 Linde Ag Verfahren zum Gießen von Magnesium
DE102011008894A1 (de) * 2011-01-19 2012-07-19 Air Liquide Deutschland Gmbh Verfahren und Düse zur Unterdrückung einer Entwicklung von eisenhaltigem Dampf

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR434070A (fr) * 1910-11-14 1912-01-24 Marcellin Reymondier Nouveau procédé de coulée et de moulage permettant d'obtenir des aciers, fontes, métaux ou alliages sains et homogènes
BE677958A (de) * 1966-03-16 1966-09-16
BE677957A (de) * 1966-03-16 1966-09-16
LU70560A1 (de) * 1973-07-24 1974-11-28

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3052936A (en) * 1956-10-01 1962-09-11 Babcock & Wilcox Co Method of continuously casting metals
US3224051A (en) * 1962-01-31 1965-12-21 Brown Fintube Co Method of introducing addition agent into a melt
US3230074A (en) * 1962-07-16 1966-01-18 Chrysler Corp Process of making iron-aluminum alloys and components thereof
US3258328A (en) * 1962-08-23 1966-06-28 Fuji Iron & Steel Co Ltd Method and apparatus for treating steel
US4089678A (en) * 1975-08-01 1978-05-16 Hanawalt Joseph D Method and product for protecting molten magnesium

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR434070A (fr) * 1910-11-14 1912-01-24 Marcellin Reymondier Nouveau procédé de coulée et de moulage permettant d'obtenir des aciers, fontes, métaux ou alliages sains et homogènes
BE677958A (de) * 1966-03-16 1966-09-16
BE677957A (de) * 1966-03-16 1966-09-16
LU70560A1 (de) * 1973-07-24 1974-11-28

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2607039A1 (fr) * 1986-11-26 1988-05-27 Air Liquide Procede de coulee d'acier comportant un inertage du bain d'acier par de l'anhydride carbonique sous forme de neige
EP0274290A1 (de) * 1986-11-26 1988-07-13 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Stahlgussverfahren mit Schutz des Stahlbades durch Kohlendioxydschnee
EP0288369A2 (de) * 1987-04-20 1988-10-26 Liquid Air Corporation Verfahren und Einrichtung zum Schutz eines flüssigen Metallstromes
EP0288369A3 (de) * 1987-04-20 1989-07-26 Liquid Air Corporation Verfahren und Einrichtung zum Schutz eines flüssigen Metallstromes

Also Published As

Publication number Publication date
AU5504686A (en) 1986-10-09
FR2579495B1 (fr) 1987-09-11
EP0196952B1 (de) 1990-09-26
CA1268044A (fr) 1990-04-24
EP0196952A3 (en) 1988-10-26
US4666511A (en) 1987-05-19
AU586856B2 (en) 1989-07-27
ATE56896T1 (de) 1990-10-15
DE3674446D1 (de) 1990-10-31
BR8601411A (pt) 1986-12-09
ZA862011B (en) 1986-10-29
JPS61235507A (ja) 1986-10-20
FR2579495A1 (fr) 1986-10-03
ES8702810A1 (es) 1987-01-16
ES553528A0 (es) 1987-01-16

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