EP0738785B1 - Procédé et installation pour le réglage de la concentration en CO de l'atmosphère d'un four pour la cémentation et carbonitruration de pièces métalliques - Google Patents

Procédé et installation pour le réglage de la concentration en CO de l'atmosphère d'un four pour la cémentation et carbonitruration de pièces métalliques Download PDF

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Publication number
EP0738785B1
EP0738785B1 EP96101732A EP96101732A EP0738785B1 EP 0738785 B1 EP0738785 B1 EP 0738785B1 EP 96101732 A EP96101732 A EP 96101732A EP 96101732 A EP96101732 A EP 96101732A EP 0738785 B1 EP0738785 B1 EP 0738785B1
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EP
European Patent Office
Prior art keywords
content
furnace
furnace atmosphere
atmosphere
carburizing
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.)
Expired - Lifetime
Application number
EP96101732A
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German (de)
English (en)
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EP0738785A1 (fr
Inventor
Max Roggatz
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Ipsen International GmbH
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Ipsen International GmbH
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Publication date
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Publication of EP0738785A1 publication Critical patent/EP0738785A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising
    • C23C8/22—Carburising of ferrous surfaces

Definitions

  • the invention relates to a method for controlling the CO content of a furnace atmosphere for carburizing and carbonitriding metallic workpieces in a furnace, the furnace atmosphere by directly feeding a mixture of an oxidizing agent, eg. B. air, and a hydrocarbon-containing fuel and optionally ammonia (NH 3 ) generated in the furnace, the CO content of the furnace atmosphere is determined and compared with a freely definable value for the CO content.
  • an oxidizing agent eg. B. air
  • NH 3 optionally ammonia
  • the invention further relates to an apparatus for performing this method.
  • the required carburizing atmosphere is generated either in separate inert gas generators (endogas) or by feeding nitrogen with methanol into the furnace.
  • the furnace has a relatively stable CO value, which in the first case results from the setting of the protective gas generator and the fuel used in the protective gas generator, and in the second case from the percentage of methanol fed into the furnace.
  • a third variant is direct gassing with hydrocarbons and an oxidizing gas component, such as. B. air or CO 2 .
  • liquid or gaseous fuels are mixed with the oxidizing agent and fed into the furnace.
  • the CO content required for the carburization is generated in the furnace by direct reaction of the fuel with the oxygen of the oxidizing agent.
  • natural gas-air fumigation is currently the most widespread. This is due to the high availability and low price of natural gas.
  • JP-A-57 177 969 describes a method for regulating the carbon potential the furnace atmosphere is known, in which the determination of the Carbon potential via the determination of the oxygen partial pressure and the determination of the CO partial pressure.
  • carbon potential can be obtained from a Enrichment gas can be added to the furnace atmosphere in a separate tank. The dependence of the soot formation on the CO content of the furnace atmosphere is not to be inferred from this publication.
  • the invention has for its object to provide a control for the CO content of the furnace atmosphere, the continuous operation without sooting in carburizing and carbonitriding furnaces even at low carburizing temperatures ( ⁇ 870 ° C) and also in the presence of ammonia (carbonitriding) Furnace chamber guaranteed.
  • the task of continuous and trouble-free operation with a regulated CO content is achieved in that when a freely adjustable minimum CO content is reached, methanol or CO 2 is added to the furnace atmosphere as a CO-forming substance.
  • the methanol fed into the furnace atmosphere becomes after the reaction CH 3 OH ⁇ CO + 2H 2 split (at furnace temperatures ⁇ 800 ° C), whereby the CO content in the furnace atmosphere rises again above the set minimum CO content.
  • An alternative CO-forming substance is CO 2 .
  • a CO content of around 12% has been found to be the minimum CO content in the furnace atmosphere emphasized that falling below this value is a strong one Soot formation and, moreover, the furnace atmosphere no longer is precisely controllable.
  • As a range for the minimum and the upper CO content there is a range between about 12% and 15% CO in the furnace atmosphere proven to be particularly suitable. Because below a CO content of 15%, the course of the CO decrease is very flat, an increase is sufficient of the CO content by adding the CO generator up to this limit of about 15% off the process for a long time with a CO content above to drive the minimum limit. In addition, this narrow range has As a result, only a little CO generator is used to increase the CO content must be kept, which in turn keeps the cost of the process low can be.
  • the device for performing the described method has one Furnace chamber and a CO analyzer arranged in the furnace chamber for Determine the CO content in the furnace atmosphere and one programmable CO controller to - depending on the CO content in the Furnace atmosphere - a valve and a pump for feeding to control a CO-forming substance stored in a tank.
  • the valve and the pump will stop when the set minimum is reached CO content switched to passage or operation. When the set one is reached The upper limit of the CO content is closed again and the pump turned off.
  • the diagram in FIG. 1 shows the course of the CO content during a carbonitriding process.
  • the CO content drops sharply in the course of the process.
  • the curve of the CO content curve runs very flat below 15% CO.
  • Below the 12% line shown as the minimum CO content limit the too low CO content in the furnace atmosphere causes the furnace to soot quickly.
  • the furnace atmosphere becomes a CO-forming substance, e.g. B. added methanol, which due to the high process temperature after the reaction CH 3 OH ⁇ CO + 2H 2 is split. Due to this CO formation due to the splitting of methanol, the CO content in the furnace atmosphere rises very quickly, which is illustrated by the steep rise in the CO curve in FIG. 1.
  • a freely adjustable upper limit is reached - 15% in FIG. 1 - the methanol supply is switched off again, so that the CO content in the furnace atmosphere decreases again as a result of the continuously ongoing process.
  • Fig. 2 is the structure of a device for performing the method described above.
  • a CO analyzer 1 the CO content of the furnace atmosphere in a furnace chamber 2 is determined.
  • the control unit also has a programmable CO controller 3, which freely adjustable values for the upper and lower CO content entered can be.
  • the CO controller 3 activates via the control path shown in dashed lines Valve 4 and a pump 5 as soon as a comparison of the CO analyzer 1 determined CO content with the entered in the CO controller 3 minimal CO content has shown that this reaches the minimum CO content has been.
  • the pump 5 controlled by the CO controller 3 then conveys the CO generator from a tank 6 through the passage valve 4 in the Furnace chamber 2.
  • the CO generator is as above described split, causing the CO content in the furnace atmosphere again increases. If the continuous adjustment of the determined by the CO analyzer 1 CO content in the furnace atmosphere with those stored in the CO controller 3 Values indicate that the entered upper CO content is reached has been, the valve 4 are closed via the CO controller 3 and the pump 5 turned off again.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Furnace Details (AREA)

Claims (5)

  1. Procédé pour le réglage de la concentration en CO d'une atmosphère de four pour la cémentation et la carbonitruration de pièces façonnées métalliques, dans un four, l'atmosphère du four étant générée par une injection directe dans le four d'un mélange constitué d'un agent d'oxydation, par exemple de l'air, et d'un combustible contenant un hydrocarbure, ainsi que, le cas échéant, d'ammoniaque (NH3), et la concentration en CO de l'atmosphère du four étant déterminée et comparée à une valeur susceptible d'être prédéterminée librement de la concentration en CO,
       caractérisé en ce que,
       lors de l'atteinte d'une concentration en CO minimale, réglable librement, de l'atmosphère du four, du méthanol ou du CO2 est amené à titre de substances formatrice de CO.
  2. Procédé selon la revendication 1, caractérisé en ce que la substance formatrice de CO est amenée à l'atmosphère du four jusqu'à ce qu'une concentration en CO supérieure, réglable librement, soit atteinte.
  3. Procédé selon la revendication 1 ou 2, caractérisé en ce que la concentration minimale en CO est d'environ 12 % CO.
  4. Procédé selon la revendication 2, caractérisé en ce que la largeur de bande de régulation de la concentration en CO est située entre environ 12 % et environ 15 % CO.
  5. Dispositif de mise en oeuvre du procédé selon l'une des revendications 1 à 4, avec une chambre de four (2) et un analyseur de CO (1) disposé dans la chambre de four (2), pour déterminer la concentration en CO dans l'atmosphère du four,
       caractérisé par
       un régulateur de CO (3) programmable, pour assurer la commande d'une valve (4) ainsi que d'une pompe (5) destinée à amener une substance formatrice de CO, en partant d'un réservoir (6), en fonction de la concentration en CO régnant dans l'atmosphère du four.
EP96101732A 1995-04-22 1996-02-07 Procédé et installation pour le réglage de la concentration en CO de l'atmosphère d'un four pour la cémentation et carbonitruration de pièces métalliques Expired - Lifetime EP0738785B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19514932A DE19514932A1 (de) 1995-04-22 1995-04-22 Verfahren und Vorrichtung zur Regelung des CO-Gehaltes einer Ofenatmosphäre zum Aufkohlen und Carbonitrieren metallischer Werkstücke
DE19514932 1995-04-22

Publications (2)

Publication Number Publication Date
EP0738785A1 EP0738785A1 (fr) 1996-10-23
EP0738785B1 true EP0738785B1 (fr) 1999-03-31

Family

ID=7760177

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96101732A Expired - Lifetime EP0738785B1 (fr) 1995-04-22 1996-02-07 Procédé et installation pour le réglage de la concentration en CO de l'atmosphère d'un four pour la cémentation et carbonitruration de pièces métalliques

Country Status (8)

Country Link
US (1) US5741371A (fr)
EP (1) EP0738785B1 (fr)
JP (1) JPH08296028A (fr)
CN (1) CN1136330C (fr)
AT (1) ATE178366T1 (fr)
CA (1) CA2174409C (fr)
DE (2) DE19514932A1 (fr)
ES (1) ES2129897T3 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3409236B2 (ja) * 1997-02-18 2003-05-26 同和鉱業株式会社 熱処理炉の雰囲気制御方法
DE19940370C2 (de) * 1999-08-25 2001-07-12 Messer Griesheim Gmbh Verfahren für die Nitrocarburierung metallischer Werkstücke
US6635121B2 (en) * 2000-02-04 2003-10-21 American Air Liquide, Inc. Method and apparatus for controlling the decarburization of steel components in a furnace
JP3884326B2 (ja) * 2002-05-22 2007-02-21 大陽日酸株式会社 浸炭用雰囲気ガス発生装置及び方法
EP2360287B1 (fr) * 2005-12-08 2013-08-07 NTN Corporation Procédé pour la nitrocementation gazeuse de composant de machine , procédé pour la fabrication d'un composant de machine et composant de machine
CN103589987B (zh) * 2013-12-06 2016-01-20 龙工（上海）精工液压有限公司 一种柱塞泵用传动轴的热处理工艺

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH628092A5 (de) * 1978-03-21 1982-02-15 Ipsen Ind Int Gmbh Verfahren und vorrichtung zur regelung des kohlenstoffpegels eines chemisch reagierenden gasgemisches.
GB2044804A (en) * 1979-03-16 1980-10-22 Boc Ltd Heat treatment method
JPS57177969A (en) * 1981-04-23 1982-11-01 Chugai Ro Kogyo Kaisha Ltd Controlling method for carbon potential in furnace
US5133813A (en) * 1990-07-03 1992-07-28 Tokyo Heat Treating Company Ltd. Gas-carburizing process and apparatus

Also Published As

Publication number Publication date
JPH08296028A (ja) 1996-11-12
EP0738785A1 (fr) 1996-10-23
CA2174409A1 (fr) 1996-10-23
CA2174409C (fr) 2009-06-23
DE19514932A1 (de) 1996-10-24
CN1136330C (zh) 2004-01-28
US5741371A (en) 1998-04-21
ATE178366T1 (de) 1999-04-15
DE59601530D1 (de) 1999-05-06
CN1136597A (zh) 1996-11-27
ES2129897T3 (es) 1999-06-16

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