EP1050592A1 - Process of heat treating metal workpieces - Google Patents

Process of heat treating metal workpieces Download PDF

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Publication number
EP1050592A1
EP1050592A1 EP00109379A EP00109379A EP1050592A1 EP 1050592 A1 EP1050592 A1 EP 1050592A1 EP 00109379 A EP00109379 A EP 00109379A EP 00109379 A EP00109379 A EP 00109379A EP 1050592 A1 EP1050592 A1 EP 1050592A1
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EP
European Patent Office
Prior art keywords
quenching
hydrogen
gas
helium
heat treatment
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.)
Ceased
Application number
EP00109379A
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German (de)
French (fr)
Inventor
Ernst Dr.-Ing. Habil. Dipl.-Ing. Wandke
Paul Dipl.-Ing. Heilmann
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.)
Linde GmbH
Original Assignee
Linde Gas AG
Linde Technische Gase GmbH
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 Linde Gas AG, Linde Technische Gase GmbH filed Critical Linde Gas AG
Publication of EP1050592A1 publication Critical patent/EP1050592A1/en
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
    • C21D1/613—Gases; Liquefied or solidified normally gaseous material
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/76—Adjusting the composition of the atmosphere

Definitions

  • the invention relates to a method for the heat treatment of metallic workpieces by heating up the workpieces and then quenching, the Quenching is performed with a cooling gas.
  • a generic method for the heat treatment of metallic workpieces is known from DE-PS 37 36 501. This is done in the furnace where the heat treatment takes place during quenching with helium, hydrogen or a Mixture of helium and hydrogen as cooling gas a cooling gas pressure p between 1 and 4 MPa set.
  • the cooling gas velocity v is set so that the product of the cooling gas pressure p and the cooling gas speed v between 10 and 250 MPa m / sec.
  • the heat treatment in a heat treatment furnace for example in a vacuum furnace, downstream quenching can either be in the furnace itself or a gas-tight chamber.
  • EP-A 0 869 189 describes a method for quenching metallic workpieces after a heat treatment, in which a cooling gas pressure p in the furnace or Quench chamber greater than 4 MPa (40 bar), preferably greater than 4 MPa and up to 5.5 MPa. This method also comes as cooling gas the gases or gas mixtures listed, and nitrogen or nitrogen-containing ones Mixtures for use.
  • the object of the present invention is a method for heat treatment specify metallic workpieces, especially with regard to the quenching process is optimized and by means of which the quality of the heat-treated metallic workpieces can be increased.
  • this is achieved by using CO, CO 2 , O 2 , H 2 S, H 2 O vapor, H 3 N, NO 3 , methanol, a saturated and / or unsaturated hydrocarbon as the cooling gas.
  • the method according to the invention is proposed that the Cooling gas nitrogen, helium, hydrogen or a mixture of helium and hydrogen is added.
  • the cold chamber coupled to a carburizing furnace particularly advantageous with a gas mixture consisting of half each Hydrogen and carbon monoxide.
  • a gas mixture consisting of half each Hydrogen and carbon monoxide.
  • excellent quenching behavior is not only achieved, it also arises during quenching itself a reducing effect on the quenched Workpiece.
  • This has not only improvements in terms of purity and Functionality of the workpiece surface, but also offers the advantage that the gas or gas mixture used for quenching without aftertreatment can be fed directly to a furnace as carbonization gas.
  • the H 2 / CO gas mixture mentioned is to be regarded as advantageous not only with regard to the quenching process but also with regard to the carburizing process, since this gas mixture represents an optimal atmosphere for carburizing case-hardening steels.
  • thermochemical treatment required reactive gas component in a concentration up to 50 vol .-%, preferably up to 15 vol .-% is added.
  • Carbon dioxide / helium cooling gas mixture has a reducing effect and through that Add 10 vol.% Carbon dioxide to nitrogen or 4 vol.% Oxygen to Hydrogen has an oxidizing effect.
  • the quenching process can be optimized and the quality of the heat treated metallic workpieces can be improved.
  • the required plant engineering Effort compared to the prior art processes not significantly enlarged.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)

Abstract

Metal heat treatment comprises quenching in gaseous carbon monoxide, carbon dioxide, oxygen, hydrogen sulfide, steam, ammoni nitrogen trioxide, methanol and/or saturated or unsaturated hydrocarbon. Preferred Features: Nitrogen, helium, hydrogen or a mixture of helium and hydrogen is added to the quenching gas.

Description

Die Erfindung betrifft ein Verfahren zur Wärmebehandlung metallischer Werkstücke durch Aufheizen der Werkstücke und anschließendes Abschrecken, wobei das Abschrecken mit einem Kühlgas durchgeführt wird.The invention relates to a method for the heat treatment of metallic workpieces by heating up the workpieces and then quenching, the Quenching is performed with a cooling gas.

Ein gattungsgemäßes Verfahren zur Wärmebehandlung metallischer Werkstücke ist aus der DE-PS 37 36 501 bekannt. Bei diesem wird in dem Ofen, in dem die Wärmebehandlung erfolgt, während des Abschreckens mit Helium, Wasserstoff oder einem Gemisch aus Helium und Wasserstoff als Kühlgas ein Kühlgasdruck p zwischen 1 und 4 MPa eingestellt. Zudem wird die Kühlgasgeschwindigkeit v so eingestellt, daß das Produkt aus Kühlgasdruck p und Kühlgasgeschwindigkeit v zwischen 10 und 250 MPa m/sec liegt.A generic method for the heat treatment of metallic workpieces is known from DE-PS 37 36 501. This is done in the furnace where the heat treatment takes place during quenching with helium, hydrogen or a Mixture of helium and hydrogen as cooling gas a cooling gas pressure p between 1 and 4 MPa set. In addition, the cooling gas velocity v is set so that the product of the cooling gas pressure p and the cooling gas speed v between 10 and 250 MPa m / sec.

Die der Wärmebehandlung in einem Wärmebehandlungsofen, beispielsweise in einem Vakuumofen, nachgeschaltete Abschreckung kann entweder im Ofen selbst oder einer gasdichten Kammer durchgeführt werden.The heat treatment in a heat treatment furnace, for example in a vacuum furnace, downstream quenching can either be in the furnace itself or a gas-tight chamber.

Aus der EP-A 0 869 189 ist ein Verfahren zur Abschreckung metallischer Werkstücke nach einer Wärmebehandlung bekannt, bei dem ein Kühlgasdruck p im Ofen oder der Abschreckkammer von mehr als 4 MPa (40 bar), vorzugsweise von mehr als 4 MPa und bis zu 5,5 MPa, eingestellt wird. Als Kühlgas kommen auch bei diesem Verfahren die angeführten Gase bzw. Gasgemische sowie Stickstoff oder Stickstoff-enthaltende Gemische zum Einsatz.EP-A 0 869 189 describes a method for quenching metallic workpieces after a heat treatment, in which a cooling gas pressure p in the furnace or Quench chamber greater than 4 MPa (40 bar), preferably greater than 4 MPa and up to 5.5 MPa. This method also comes as cooling gas the gases or gas mixtures listed, and nitrogen or nitrogen-containing ones Mixtures for use.

Neben den erwähnten Abschreckverfahren sind seit längerem Abschreckprozesse bekannt, bei denen das Behandlungsgut in einem Salz- oder Ölbad abgeschreckt wird. Diese Prozesse sind jedoch insbesondere aus Umweltschutzgründen als nachteilig anzusehen.In addition to the mentioned quenching processes, there have been quenching processes for a long time known in which the material to be treated is quenched in a salt or oil bath becomes. However, these processes are particularly considered for environmental reasons to look at disadvantageously.

Aufgabe der vorliegenden Erfindung ist es, ein Verfahren zur Wärmebehandlung metallischer Werkstücke anzugeben, das insbesondere hinsichtlich des Abschreckprozesses optimiert ist und mittels dessen die Qualität der wärmebehandelten metallischen Werkstücke erhöht werden kann.The object of the present invention is a method for heat treatment specify metallic workpieces, especially with regard to the quenching process is optimized and by means of which the quality of the heat-treated metallic workpieces can be increased.

Entsprechend dem erfindungsgemäßen Verfahren wird dies dadurch erreicht, daß als Kühlgas CO, CO2, O2, H2S, H2O-Dampf, H3N, NO3, Methanol, ein gesättigter und/oder ungesättigter Kohlenwasserstoff verwendet wird.According to the method of the invention, this is achieved by using CO, CO 2 , O 2 , H 2 S, H 2 O vapor, H 3 N, NO 3 , methanol, a saturated and / or unsaturated hydrocarbon as the cooling gas.

Es hat sich überraschenderweise gezeigt, daß mit den genannten Gasen bzw. Gasgemischen der Abschreckprozeß positiv beeinflußt wird. Derartige Gase bzw. Gasgemische wirken im wesentlichen in zwei Richtungen. Zum einen wird die Abschreckwirkung nach einem ähnlichen Mechanismus, wie er von der Zugabe von Inertgasen bekannt ist, verbessert; zum anderen bewirken die genannten Gase bzw. Gasgemische eine Verstärkung bzw. Unterstützung der beabsichtigten chemischen Wirkung, die beispielsweise oxidierend, reduzierend, nitrierend, etc. sein kann. Des weiteren können schädigende Einflüsse auf während der Wärmebehandlung oder zuvor auf die abzuschreckenden Werkstücke aufgebrachte Schichten, Diffusionszonen, etc. verhindert, zumindest jedoch verringert werden.Surprisingly, it has been shown that with the gases or Gas mixtures the quenching process is positively influenced. Such gases or Gas mixtures act essentially in two directions. For one thing, the Quenching effect by a mechanism similar to that of adding Inert gases is known, improved; on the other hand, the gases or Gas mixtures reinforce or support the intended chemical Effect that can be, for example, oxidizing, reducing, nitriding, etc. Of further damaging influences can occur during the heat treatment or layers, diffusion zones, previously applied to the workpieces to be quenched etc. prevented, but at least reduced.

Das erfindungsgemäße Verfahren weiterbildend wird vorgeschlagen, daß dem Kühlgas Stickstoff, Helium, Wasserstoff oder ein Gemisch aus Helium und Wasserstoff zugesetzt wird.The method according to the invention is proposed that the Cooling gas nitrogen, helium, hydrogen or a mixture of helium and hydrogen is added.

Es hat sich gezeigt, daß das erfindungsgemäße Verfahren dann besonders vorteilhaft anwendbar ist, wenn der Abschreckprozeß bzw. die dafür erforderliche Vorrichtung in den sog. Gasbereich der Wärmebehandlungsanlage integriert werden kann. In diesen Fällen muß zu der Luft bzw. Umgebungsatmosphäre keine zusätzlich aufwendige Abschottung erfolgen.It has been shown that the method according to the invention is then particularly advantageous is applicable if the quenching process or the device required therefor in the so-called gas area of the heat treatment system can be integrated. In these Cases do not have to be additional complex to the air or ambient atmosphere Foreclosure is carried out.

Weiterhin läßt sich beispielsweise die an einen Aufkohlungsofen gekoppelte Kaltkammer besonders vorteilhaft mit einem Gasgemisch, bestehend jeweils zur Hälfte aus Wasserstoff und Kohlenmonoxid, betreiben. Bei Verwendung dieses Gasgemisches wird nicht nur ein ausgezeichnetes Abschreckverhalten erzielt, es stellt sich auch während des Abschreckens selbst eine reduzierende Wirkung auf das abzuschreckende Werkstück ein. Dies hat nicht nur Verbesserungen bzgl. der Reinheit sowie der Funktionalität der Werkstückoberfläche zur Folge, sondern bietet zudem den Vorteil, daß das zur Abschreckung verwendete Gas bzw. Gasgemisch ohne Nachbehandlung unmittelbar als Kohlungsgas einem Ofen zugeführt werden kann.Furthermore, for example, the cold chamber coupled to a carburizing furnace particularly advantageous with a gas mixture consisting of half each Hydrogen and carbon monoxide. When using this gas mixture excellent quenching behavior is not only achieved, it also arises during quenching itself a reducing effect on the quenched Workpiece. This has not only improvements in terms of purity and Functionality of the workpiece surface, but also offers the advantage that the gas or gas mixture used for quenching without aftertreatment can be fed directly to a furnace as carbonization gas.

Im Zusammenhang mit diesem Beispiel ist anzumerken, daß das erwähnte H2/CO-Gasgemisch nicht nur im Hinblick auf den Abschreckprozeß, sondern auch im Hinblick auf den Aufkohlungsprozeß als vorteilhaft anzusehen ist, da diese Gasmischung eine optimale Atmosphäre zum Aufkohlen von Einsatzstählen darstellt.In connection with this example, it should be noted that the H 2 / CO gas mixture mentioned is to be regarded as advantageous not only with regard to the quenching process but also with regard to the carburizing process, since this gas mixture represents an optimal atmosphere for carburizing case-hardening steels.

Das erfindungsgemäße Verfahren zur Wärmebehandlung metallischer Werkstücke weiterbildend wird vorgeschlagen, daß der für die thermochemische Behandlung erforderliche reaktive Gasbestandteil in einer Konzentration bis zu 50 Vol.-%, vorzugsweise bis zu 15 Vol.-%, zugesetzt wird.The method according to the invention for the heat treatment of metallic workpieces further education is proposed that for thermochemical treatment required reactive gas component in a concentration up to 50 vol .-%, preferably up to 15 vol .-% is added.

Abhängig von den jeweiligen Kombinationen aus reaktivem Gas und Kühlgas(gemisch) können oftmals bereits durch die Zugabe geringer Mengen an reaktivem Gas - gemeint sind hier Mengen im Bereich von Bruchteilen von Prozenten bis zu wenigen Prozenten - die geschilderten Vorteile erreicht werden.Depending on the respective combinations of reactive gas and cooling gas (mixture) can often be achieved by adding small amounts of reactive Gas - here we mean quantities ranging from fractions of percent to a few percent - the described advantages can be achieved.

Beispielsweise wird durch die Zugabe von 0,5 bis 5 Vol.-% Kohlenmonoxid zu einem Kohlendioxid/Helium-Kühlgasgemisch eine reduzierende Wirkung und durch die Zugabe von 10 Vol.-% Kohlendioxid zu Stickstoff oder von 4 Vol.-% Sauerstoff zu Wasserstoff eine oxidierende Wirkung erzielt.For example, by adding 0.5 to 5% by volume of carbon monoxide to one Carbon dioxide / helium cooling gas mixture has a reducing effect and through that Add 10 vol.% Carbon dioxide to nitrogen or 4 vol.% Oxygen to Hydrogen has an oxidizing effect.

Es ist zudem denkbar, daß die gewünschte Wirkung der Zugabe von reaktivem Gas erst während des Abschreckprozesses zum Tragen kommt. Dies wird z. B. durch die Zugabe von 5 Vol.-% Methan erreicht. Das Methan zersetzt sich bei Härtetemperaturen von ca. 1100°C beim Auftreffen auf die Oberfläche des abzuschreckenden Werkstückes zu Kohlenstoff und Wasserstoffatomen und entfaltet erst dann seine reduzierende Wirkung.It is also conceivable that the desired effect of the addition of reactive gas only comes into play during the quenching process. This is e.g. B. by the Addition of 5 vol .-% methane reached. The methane decomposes at hardness temperatures of approx. 1100 ° C when striking the surface of the quenched Workpiece to carbon and hydrogen atoms and only then unfolds its reducing effect.

Mittels des erfindungsgemäßen Verfahrens zur Wärmebehandlung metallischer Werkstücke kann der Abschreckprozeß optimiert und die Qualität der wärmebehandelten metallischen Werkstücke verbessert werden. Hierbei wird der erforderliche anlagentechnische Aufwand gegenüber den zum Stand der Technik zählenden Verfahren nicht wesentlich vergrößert.By means of the method according to the invention for the heat treatment of metallic workpieces the quenching process can be optimized and the quality of the heat treated metallic workpieces can be improved. Here, the required plant engineering Effort compared to the prior art processes not significantly enlarged.

Claims (3)

Verfahren zur Wärmebehandlung metallischer Werkstücke durch Aufheizen der Werkstücke und anschließendes Abschrecken, wobei das Abschrecken mit einem Kühlgas durchgeführt wird, dadurch gekennzeichnet, daß als Kühlgas CO, CO2, O2, H2S, H2O-Dampf, H3N, NO3, Methanol, ein gesättigter und/oder ungesättigter Kohlenwasserstoff verwendet wird.Process for the heat treatment of metallic workpieces by heating up the workpieces and subsequent quenching, the quenching being carried out with a cooling gas, characterized in that CO, CO 2 , O 2 , H 2 S, H 2 O steam, H 3 N as cooling gas NO 3 , methanol, a saturated and / or unsaturated hydrocarbon is used. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß dem Kühlgas Stickstoff, Helium, Wasserstoff oder ein Gemisch aus Helium und Wasserstoff zugesetzt wird.A method according to claim 1, characterized in that the cooling gas Nitrogen, helium, hydrogen or a mixture of helium and hydrogen is added. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der für die thermochemische Behandlung erforderliche reaktive Gasbestandteil in einer Konzentration bis zu 50 Vol.-%, vorzugsweise bis zu 15 Vol.-%, zugesetzt wird.A method according to claim 1 or 2, characterized in that the for thermochemical treatment required reactive gas component in one Concentration up to 50 vol .-%, preferably up to 15 vol .-%, is added.
EP00109379A 1999-05-03 2000-05-02 Process of heat treating metal workpieces Ceased EP1050592A1 (en)

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DE1999120297 DE19920297A1 (en) 1999-05-03 1999-05-03 Process for the heat treatment of metallic workpieces
DE19920297 1999-05-03

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2844809A1 (en) * 2002-09-20 2004-03-26 Air Liquide Rapid cooling of metal components involves using a cooling gas mixture including a gas that absorbs infrared radiation to improve heat transfer within the component by convection and radiation
FR2863628A1 (en) * 2003-12-11 2005-06-17 Etudes Const Mecaniques Device for the carbon dioxide quenching of steel components after they have been subjected to a thermochemical treatment operation such as cementation
FR2869046A1 (en) * 2004-04-19 2005-10-21 Francis Pelissier PROCESS FOR TEMPERING GAS
WO2007031667A1 (en) * 2005-09-16 2007-03-22 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method for preventing formation of carbon monoxide during a gas quenching operation

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2288803A (en) * 1941-10-10 1942-07-07 Socony Vacuum Oil Co Inc Metal treating
DE4208485C1 (en) * 1992-03-17 1993-02-11 Joachim Dr.-Ing. 7250 Leonberg De Wuenning
US5373893A (en) * 1992-10-19 1994-12-20 International Business Machines Corporation Method and apparatus for cooling thermally massive parts in a continuous furnace
DE19709957A1 (en) * 1997-03-11 1998-09-17 Linde Ag Process for gas quenching of metallic workpieces after heat treatments

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE767719C (en) * 1940-07-11 1953-04-09 Dortmund Hoerder Huettenver A Process for quenching workpieces made of iron and steel
DE3736501C1 (en) * 1987-10-28 1988-06-09 Degussa Process for the heat treatment of metallic workpieces

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2288803A (en) * 1941-10-10 1942-07-07 Socony Vacuum Oil Co Inc Metal treating
DE4208485C1 (en) * 1992-03-17 1993-02-11 Joachim Dr.-Ing. 7250 Leonberg De Wuenning
US5373893A (en) * 1992-10-19 1994-12-20 International Business Machines Corporation Method and apparatus for cooling thermally massive parts in a continuous furnace
DE19709957A1 (en) * 1997-03-11 1998-09-17 Linde Ag Process for gas quenching of metallic workpieces after heat treatments

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2844809A1 (en) * 2002-09-20 2004-03-26 Air Liquide Rapid cooling of metal components involves using a cooling gas mixture including a gas that absorbs infrared radiation to improve heat transfer within the component by convection and radiation
WO2004027098A1 (en) * 2002-09-20 2004-04-01 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Rapid cooling method for parts by convective and radiative transfer
KR100953818B1 (en) * 2002-09-20 2010-04-21 레르 리키드 쏘시에떼 아노님 뿌르 레드 에렉스뿔라따시옹 데 프로세데 조르즈 클로드 Method and installation for rapidly cooling metal parts using a pressurized cooling gas
FR2863628A1 (en) * 2003-12-11 2005-06-17 Etudes Const Mecaniques Device for the carbon dioxide quenching of steel components after they have been subjected to a thermochemical treatment operation such as cementation
WO2005066376A1 (en) * 2003-12-11 2005-07-21 Etudes Et Constructions Mecaniques Device for tempering steel parts
FR2869046A1 (en) * 2004-04-19 2005-10-21 Francis Pelissier PROCESS FOR TEMPERING GAS
WO2005108629A1 (en) * 2004-04-19 2005-11-17 Francis Pelissier Gas quenching method
WO2007031667A1 (en) * 2005-09-16 2007-03-22 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method for preventing formation of carbon monoxide during a gas quenching operation
FR2890979A1 (en) * 2005-09-16 2007-03-23 Air Liquide METHOD FOR PREVENTING THE FORMATION OF CARBON MONOXIDE DURING A GAS TREATMENT OPERATION

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