EP0261461A2 - Procédé et appareil pour le traitement thermique de pièces métalliques - Google Patents

Procédé et appareil pour le traitement thermique de pièces métalliques Download PDF

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Publication number
EP0261461A2
EP0261461A2 EP87112804A EP87112804A EP0261461A2 EP 0261461 A2 EP0261461 A2 EP 0261461A2 EP 87112804 A EP87112804 A EP 87112804A EP 87112804 A EP87112804 A EP 87112804A EP 0261461 A2 EP0261461 A2 EP 0261461A2
Authority
EP
European Patent Office
Prior art keywords
furnace
gas
continuous furnace
nitrogen
continuous
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
EP87112804A
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German (de)
English (en)
Other versions
EP0261461B1 (fr
EP0261461A3 (en
Inventor
Reinhard Dipl.-Ing. Strigl
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 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 GmbH filed Critical Linde GmbH
Priority to AT87112804T priority Critical patent/ATE89868T1/de
Publication of EP0261461A2 publication Critical patent/EP0261461A2/fr
Publication of EP0261461A3 publication Critical patent/EP0261461A3/de
Application granted granted Critical
Publication of EP0261461B1 publication Critical patent/EP0261461B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • 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
    • C21D1/763—Adjusting the composition of the atmosphere using a catalyst

Definitions

  • the invention relates to a method for the heat treatment of metallic workpieces in a gas-heated continuous furnace under the action of a gas atmosphere, which consists essentially of nitrogen, hydrogen and carbon monoxide, and to a continuous furnace for carrying out the method.
  • the heat treatment of metallic workpieces is often carried out in continuous furnaces, to which a treatment gas which is based on the type of heat treatment is supplied from the outside.
  • a treatment gas which is based on the type of heat treatment is supplied from the outside.
  • roller hearth furnaces for annealing semi-finished products made of iron or non-ferrous metals are known, which are equipped with so-called exogas, which in gas generators by exothermic combustion of hydrocarbons with air, or with so-called endogas, which in reactors filled with catalysts with the supply of heat also from hydrocarbon-air. Mixtures are generated, operated.
  • the treatment gases produced in both processes essentially contain nitrogen, hydrogen and carbon monoxide and, under certain circumstances, also admixtures of carbon dioxide and water vapor.
  • the exact mixing ratio of the components is chosen as it is with the respective type of Heat treatment in the main treatment zone, for example in the hot zone of the continuous furnace, is required.
  • control and regulating methods are known with which the mixing ratio is influenced as a function of a size measured in the oven (VDI-Zeitung 98 (1956), No. 24, pages 1486 to 1490).
  • the invention is therefore based on the object of making the known methods for the heat treatment of metallic workpieces in gas-fired continuous furnaces more economical.
  • This object is achieved in that the gas atmosphere from a treatment gas containing nitrogen, hydrogen and carbon monoxide, which is fed to the continuous furnace in the region of its heating zone and which is generated immediately before it enters the continuous furnace by catalytic reaction of a gas containing hydrocarbons and air, and nitrogen , which is fed to the continuous furnace, on both sides of the supply point for the treatment gas, between the furnace inlet and the heating zone and between the heating zone and the furnace outlet.
  • a gas atmosphere profile extending in the direction of the longitudinal extension of the continuous furnace is optimally built up, which starts from the furnace inlet with a zone of low reactivity, then reaches the highest reactivity in the region of the hot zone and finally in the region of the furnace outlet drops again to low reactivity.
  • the process according to the invention thus leads to a higher reactivity in the hot zone of the furnace, without the furnace atmosphere in the vicinity of the furnace inlet and outlet becoming more toxic or flammable than with exogas.
  • a direct consequence of this procedure is a considerable saving in terms of the consumption of hydrocarbon-containing gases, which can cost up to over 30%.
  • the process according to the invention in addition to the advantage of its increased economic efficiency compared to known processes, also brings about an improvement in the quality, in particular the uniformity, of the treated workpieces, which is based on the fact that the composition of the gas atmosphere at every point in the furnace can be set in an optimal manner.
  • an essential requirement for this advantage is the generation of the treatment gas by catalytic conversion immediately before it enters the continuous furnace.
  • the gas atmosphere formed in the process according to the invention has a high buffering effect against air ingress and leaks in the radiant tube burners. In addition, soot formation and damage to the furnace lining are reliably avoided with the method according to the invention.
  • the quantitative ratio between the treatment gas and the separately supplied nitrogen is advantageously selected such that the furnace atmosphere in the regions adjacent to the furnace inlet and outlet is less than 20%, preferably less than 10%, carbon monoxide and less than 30%, preferably less than 10%, contains hydrogen.
  • the continuous furnace is heated by means of a jet tube burner and the treatment gas is fed to the continuous furnace via a cross section which is arranged concentrically with the burner chamber and at least one of the jet tube burners which is arranged in the region of the hot zone and is filled with catalyst.
  • Preferred areas of application of the method according to the invention are recrystallization and the carbon-neutral or decarburizing annealing of semi-finished products in roller hearth furnaces.
  • a continuous furnace for carrying out the method according to the invention with jet tube burners arranged over its longitudinal extent is advantageously designed such that at least one of the jet tube burners arranged in the area of the hot zone of the continuous furnace has a cross section arranged concentrically with the burner chamber and filled with catalyst for the generation of the treatment gas and in With regard to the longitudinal extent of the continuous furnace, gas feeds for nitrogen are arranged on both sides of the radiant tube burner (s) having a cross section filled with catalyst, in the region between the furnace inlet and the hot zone and in the region between the hot zone and the furnace outlet.
  • the roller hearth furnace 1 has a furnace inlet 2, from which metallic workpieces are fed continuously or discontinuously through the furnace 1 to the furnace outlet 3 by means of transport rollers 4.
  • the furnace 1 is heated by a number of radiant tube burners 5 with natural gas as the fuel gas so that the workpieces passing through the furnace 1, e.g. should be annealed in a carbon-neutral manner, first heated slowly, then reaching the highest temperature approximately in the middle of the furnace and finally slowly cooling the furnace outlet 3 again.
  • a 6 of the jet tube burner 5 is designed as an internally heated catalytic reactor in that the burner chamber is surrounded concentrically by an annular space filled with catalyst for generating the treatment gas. Also owns the furnace 1 has two gas feeds 7 which are arranged on both sides in the longitudinal direction of the furnace to the jet tube burner 6 which is designed as a catalytic reactor. In the case of larger or longer ovens, several special jet tube burners 6 and / or further gas feeds 7 can also be provided.
  • a natural gas / air mixture is fed to the jet tube burners 5 for heating.
  • the natural gas-air mixture is additionally fed to the second cross section containing the catalyst, where a treatment gas with approximately 40% nitrogen, 38% hydrogen and 18% carbon monoxide is produced by endothermic reaction and through a gas distributor 8 is blown into the interior of the furnace 1.
  • pure nitrogen is introduced into the furnace 1 via the gas feeds 7, which dilutes the treatment gas in the region of the furnace inlet 2 and the furnace outlet 3 so that the gas atmosphere there only contains about 8% hydrogen and also about 8% carbon monoxide.
  • a gas atmosphere profile is built up in this way in furnace 1 over its longitudinal extent, which has its highest reactivity in the hot zone and its lowest reactivity at furnace inlet 2 and at furnace outlet 3.
  • the changing composition of the furnace atmosphere can be caused, on the one hand, by changes in the mixing ratio of the natural gas-air mixture which is fed to the furnace 1 via the jet tube burner 6 designed as a catalytic reactor, and, on the other hand, by changes in the amount of nitrogen introduced into the furnace 1 via the gas feeds 7 can be adapted in any way and extremely precisely to the respective requirements.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Furnace Details (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Tunnel Furnaces (AREA)
  • Processing Of Solid Wastes (AREA)
EP87112804A 1986-09-10 1987-09-02 Procédé et appareil pour le traitement thermique de pièces métalliques Expired - Lifetime EP0261461B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87112804T ATE89868T1 (de) 1986-09-10 1987-09-02 Verfahren und vorrichtung zur waermebehandlung metallischer werkstuecke.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863630833 DE3630833A1 (de) 1986-09-10 1986-09-10 Verfahren und vorrichtung zur waermebehandlung metallischer werkstuecke
DE3630833 1986-09-10

Publications (3)

Publication Number Publication Date
EP0261461A2 true EP0261461A2 (fr) 1988-03-30
EP0261461A3 EP0261461A3 (en) 1989-03-15
EP0261461B1 EP0261461B1 (fr) 1993-05-26

Family

ID=6309316

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87112804A Expired - Lifetime EP0261461B1 (fr) 1986-09-10 1987-09-02 Procédé et appareil pour le traitement thermique de pièces métalliques

Country Status (5)

Country Link
EP (1) EP0261461B1 (fr)
AT (1) ATE89868T1 (fr)
BR (1) BR8704618A (fr)
DE (2) DE3630833A1 (fr)
ES (1) ES2042524T3 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0435033A1 (fr) * 1989-12-23 1991-07-03 Linde Aktiengesellschaft Procédé pour la préparation et la distribution de gaz de traitement pour traitements thermiques
EP0458183A2 (fr) * 1990-05-19 1991-11-27 Linde Aktiengesellschaft Procédé pour la mise à disposition de gaz de traitement pour traitements thermiques
DE4343927C1 (de) * 1993-12-22 1995-01-05 Linde Ag Verfahren zur Wärmebehandlung von Werkstücken unter Behandlungsgas
EP0778354A1 (fr) * 1995-12-07 1997-06-11 Linde Aktiengesellschaft Procédé d'alimentation de gaz protecteur dans un four de traitement thermique et installation de traitement thermique
EP0856587A1 (fr) * 1997-01-29 1998-08-05 Praxair Technology, Inc. Procédé pour le traitement thermique de pièces métalliques à base de fer dans une atmosphère active à potentiel de carbone élevé
WO2005035799A1 (fr) * 2003-10-08 2005-04-21 Messer Austria Gmbh Procede de traitement thermique de matieres ferreuses

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3842372C2 (de) * 1988-12-16 1996-10-02 Induktionserwaermung Fritz Due Vorrichtung zur Wärmebehandlung metallischer Werkstücke
FR2668584B1 (fr) * 1990-10-26 1994-03-18 Lair Liquide Procede d'elaboration d'une atmosphere de traitement thermique et installation de traitement thermique.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD31283A (fr) *
AT258994B (de) * 1963-09-21 1967-12-27 Werner Goehring Verfahren zum Erzeugen einer Ofenatmosphäre für die Wärmebehandlung von Metallen, insbesondere von Stahl
DE2758024A1 (de) * 1977-03-28 1978-10-12 Thaelmann Schwermaschbau Veb Einrichtung zur schutzgaserzeugung im ofenraum
EP0180953A2 (fr) * 1984-11-08 1986-05-14 Linde Aktiengesellschaft Procédé et dispositif pour la production d'une atmosphère protectrice

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD31283A (fr) *
AT258994B (de) * 1963-09-21 1967-12-27 Werner Goehring Verfahren zum Erzeugen einer Ofenatmosphäre für die Wärmebehandlung von Metallen, insbesondere von Stahl
DE2758024A1 (de) * 1977-03-28 1978-10-12 Thaelmann Schwermaschbau Veb Einrichtung zur schutzgaserzeugung im ofenraum
EP0180953A2 (fr) * 1984-11-08 1986-05-14 Linde Aktiengesellschaft Procédé et dispositif pour la production d'une atmosphère protectrice

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HTM HAERTEREI-TECHNISCHE MITTEILUNGEN, Band 41, Nr. 2, Maerz/April 1986, Seiten 107-108, München; G. Boehm: 'Bessere Wirtschaftlichkeit beim Blankglühen durch Cryogen-Schnellkühlung' *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0435033A1 (fr) * 1989-12-23 1991-07-03 Linde Aktiengesellschaft Procédé pour la préparation et la distribution de gaz de traitement pour traitements thermiques
EP0458183A2 (fr) * 1990-05-19 1991-11-27 Linde Aktiengesellschaft Procédé pour la mise à disposition de gaz de traitement pour traitements thermiques
EP0458183A3 (en) * 1990-05-19 1992-04-01 Linde Aktiengesellschaft Method for making available treatment gases for heat treatments
DE4343927C1 (de) * 1993-12-22 1995-01-05 Linde Ag Verfahren zur Wärmebehandlung von Werkstücken unter Behandlungsgas
EP0778354A1 (fr) * 1995-12-07 1997-06-11 Linde Aktiengesellschaft Procédé d'alimentation de gaz protecteur dans un four de traitement thermique et installation de traitement thermique
EP0856587A1 (fr) * 1997-01-29 1998-08-05 Praxair Technology, Inc. Procédé pour le traitement thermique de pièces métalliques à base de fer dans une atmosphère active à potentiel de carbone élevé
WO2005035799A1 (fr) * 2003-10-08 2005-04-21 Messer Austria Gmbh Procede de traitement thermique de matieres ferreuses

Also Published As

Publication number Publication date
EP0261461B1 (fr) 1993-05-26
ES2042524T3 (es) 1993-12-16
BR8704618A (pt) 1988-04-26
ATE89868T1 (de) 1993-06-15
DE3785989D1 (de) 1993-07-01
DE3630833A1 (de) 1988-03-17
EP0261461A3 (en) 1989-03-15

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