EP0080124B1 - Procédé de cémentation de pièces métalliques - Google Patents

Procédé de cémentation de pièces métalliques Download PDF

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Publication number
EP0080124B1
EP0080124B1 EP82110429A EP82110429A EP0080124B1 EP 0080124 B1 EP0080124 B1 EP 0080124B1 EP 82110429 A EP82110429 A EP 82110429A EP 82110429 A EP82110429 A EP 82110429A EP 0080124 B1 EP0080124 B1 EP 0080124B1
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EP
European Patent Office
Prior art keywords
carbon
gas
workpieces
addition
duration
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
Application number
EP82110429A
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German (de)
English (en)
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EP0080124A3 (en
EP0080124A2 (fr
Inventor
Thomas Dipl.-Ing. Mahlo
Karl Dipl.-Chem Dörhöfer
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
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Linde GmbH
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Publication date
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Publication of EP0080124A2 publication Critical patent/EP0080124A2/fr
Publication of EP0080124A3 publication Critical patent/EP0080124A3/de
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Publication of EP0080124B1 publication Critical patent/EP0080124B1/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
    • 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 case hardening metallic workpieces, the workpieces being exposed to the action of a carbon-containing gas mixture, to which one or more carbon-containing gas component (s) is (are) added in a pulsating manner during its action on the workpieces.
  • Pulsating addition of a carbon-containing gas component means adding it to the gas mixture during numerous cycles consisting of two different phases. In the first phase of a cycle, the carbon-containing gas is added to the gas mixture in a pulsed manner and the carbon potential of the gas atmosphere is raised to a certain level. In the second phase, the supply of carbon-containing gas is interrupted, that is, a carbon-containing gas is supplied to the gas mixture. This reduces the carbon potential of the gas atmosphere.
  • DE-A-2 851 982 relates to a method for controlling carburizing processes in the vacuum region.
  • a carbon-containing gas is pumped out and renewed when a certain degree of decay of the gas has been reached.
  • DE-C-726 134 discloses a method for carburizing metallic workpieces.
  • a certain gas atmosphere is supplied to the interior of the furnace. Pressure fluctuations are caused in the gas atmosphere in the furnace interior. For this purpose, a larger amount of gas is introduced into the interior of the furnace, so that the pressure increases abruptly. Gas escapes through openings in the furnace so that the pressure in the interior drops to the outlet pressure within a few minutes.
  • EP-A-49 531 describes a process for case hardening metallic workpieces, in which workpieces in a furnace are exposed to the action of a carbon-containing gas mixture at high temperatures and pressure fluctuations are generated in the gas mixture with a period that is considerably shorter compared to the duration of the heat treatment .
  • the invention is based on the object of specifying a method of the type mentioned at the outset with which workpieces can be carburized or carbonitrided uniformly, carbides formed being largely removed.
  • the carburizing or carbonitriding process is no longer divided exclusively into cycles consisting of two phases. Rather, the inventive method for case hardening is composed of several intervals, each of which consists of several cycles followed by a pause.
  • Cycle - as in the known method - is to be understood as the brief addition of a hydrocarbon to the gas mixture with subsequent interruption of the hydrocarbon supply.
  • the carbon concentration in the edge area of the workpieces drops in every interval.
  • the gradient of the carbon content and therefore the carbon transition in the workpiece is very high.
  • the amount of carbon-containing gas supplied in a cycle or the number of cycles is selected so that the supply of the carbon-containing gas is cut off as soon as carbon saturation is reached in the edge layer of the workpieces.
  • the total carburizing time is made up of the periods in which carbon is introduced into the workpiece and the periods in which the carbon diffuses in the workpiece. According to the invention, the duration of the carbon introduction is considerably shorter than that of the diffusion.
  • the process according to the invention causes the very stable carbides to dissolve during an interval, so that an excellent, surface oxidation-free surface quality of the workpieces is achieved. Because of this feature, the proposed method can also be used in push-through furnaces.
  • the amount of nitrogen supplied per unit of time is increased for the duration of the pulsating addition of the carbon-containing gas component (s).
  • the furnace in which the workpieces are treated is constantly gassed with nitrogen to ensure an inert basic gas atmosphere in the furnace chamber.
  • the amount of nitrogen is increased for the duration of the pulsating hydrocarbon addition in order not to let the concentration of the hydrocarbon radicals become too high. Otherwise they would react with each other and form soot and would no longer contribute to carburization.
  • the pause lasts a factor of 10 to 100 longer than the previous cycles.
  • a particularly simple regulation is possible in the method according to the invention if, according to an advantageous variant, the duration of the cycles is kept constant during case hardening.
  • the carbon-containing gas is consequently pulsed into the furnace chamber at constant time intervals.
  • the gas atmosphere is formed exclusively from an inert gas, in particular nitrogen, and a carbon-containing gas, in particular propane.
  • An annealing furnace 1 is connected via a line 2 to a soot sensor 3 and a control unit 4.
  • the gas components nitrogen and a hydrocarbon in the exemplary embodiment propane, are now introduced into the annealing furnace 1.
  • Supply lines 5 (nitrogen) and 6 (propane) are used for this.
  • Valves 7, 8, 9, 10 and 11 control the addition of nitrogen and propane from the appropriate tanks in which these components are stored in liquid form. Nitrogen and propane are mixed before entering the annealing furnace 1 and passed into the furnace via a line 12.
  • valve 9 in a line 13 is open, while valves 7 and 10 are closed. At this point, the furnace atmosphere consists essentially of nitrogen.
  • the carburizing or carbonitriding process begins as soon as a suitable temperature of approx. 800 to 1000 ° C has been reached in the furnace.
  • solenoid valve 10 is opened according to the invention.
  • Valve 10 is opened and closed by the control unit 4 at constant time intervals.
  • a certain amount of nitrogen is always passed into the furnace per unit time during case hardening.
  • the amount of nitrogen supplied is increased in order not to make the concentration of the hydrocarbon radicals too great. Otherwise the radicals would react with one another and form soot.
  • solenoid valve 7 in one Bypass line 14 opened by the control unit 4.
  • the propane is unstable at the high temperatures prevailing in the interior of the annealing furnace and disintegrates spontaneously.
  • the fission products are very reactive and enable the workpiece surface layer to be saturated quickly with carbon. Because of the resulting significant carbon potential difference between the workpiece surface and the core, the carbon quickly diffuses into the edge layer of the workpieces.
  • Soot can now be formed in the gas mixture.
  • the amount of propane is reduced before a minimum soot value is reached.
  • the value determined by the sensor 3 is sent to the control unit 4, in which the measured value is compared with a predetermined setpoint signal. A difference between the measured value and setpoint signal is converted into a signal by which a control valve 11 in the supply line 6 for propane is controlled.
  • valve 10 - triggered by control unit 4 - is closed for a pause which lasts longer than the previous cycles and only nitrogen is fed via line 13 with valve 9 into the furnace.
  • the carbon concentration in the edge region of the workpiece drops again, so that at the beginning of the interval consisting of several cycles with a subsequent pause, the gradient and thus the carbon transition into the workpiece is high.
  • the carbon not only diffuses into the workpiece, but also the unwanted carbides on the workpiece surface are redissolved and removed.
  • valves 7 and 10 are closed and the workpieces are lowered to the hardening temperature.
  • the carbon content in the gas mixture (e.g. in% by volume) is shown schematically against time (in seconds).
  • an interval of the method according to the invention is shown which lasts from the time zero to the time T '.
  • the carbon content of the gas mixture is briefly increased in several cycles, each of which takes time t.
  • a cycle consists of phase I (duration e ) and phase 11 (duration t 2 ).
  • phase I propane is added to the gas mixture in pulses, while in phase 11 no propane is added to the gas mixture.
  • phase 11 the carbon content therefore decreases.
  • the carbon content does not drop to 0. It is only in the pause (duration T) after several cycles (only the first four cycles in the first interval are shown in the diagram) that no propane is fed into the furnace the carbon content to 0.
  • a typical interval contains up to 15 cycles.
  • the addition periods depend on the furnace volume and the tightness of the furnace.
  • phase I lasts 5 to 15 seconds
  • phase 11, on the other hand 15 to 60 seconds.
  • Several cycles e.g. 10 with a total duration of 5 minutes
  • a break of e.g. T - 30 minutes on so that an interval lasts about 35 minutes.
  • the number of cycles of the method according to the invention is reduced by a factor of 3 compared to the known method.
  • the method according to the invention enables rapid case hardening of workpieces with low consumption of carbon carriers. Since carbides formed are redissolved by the process according to the invention, push-through furnaces can also be used in this process.

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  • 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)
  • Contacts (AREA)
  • Regulation And Control Of Combustion (AREA)
  • Arc Welding Control (AREA)

Claims (5)

1.- Procédé de cémentation de pièces métalliques, où les pièces sont soumises à l'action d'un mélange gazeux contenant du carbone, auquel sont ajoutés, de façon pulsée, un ou plusieurs composants gazeux contenant du carbone pendant l'action du mélange gazeux sur les pièces, caractérisé en ce que l'addition du ou des composants contenant du carbone est interrompue après plusieurs cycles se composant chacun d'une étape d'admission pulsée d'un gaz contenant du carbone et d'une étape suivante sans addition de gaz contenant du carbone et est à nouveau reprise après écoulement d'une pause qui a une durée multipliée par un factur compris entre 10 et 100 par rapport à celle d'un cycle.
2.- Procédé selon la revendication 1, faisant intervenir un mélange gazeux contenant de l'azote, caractérisé en ce que la quantité d'azote introduite par unité de temps est augmentée pendant la durée de l'admission pulsée du ou des composants gazeux contenant du carbone.
3.- Procédé selon une des revendications 1 et 2, caractérisé en ce que les pauses sont allongées en fonction de l'augmentation de la durée du processus de carburation.
4.- Procédé selon l'une des revendications 1 a 3, caractérisé en ce que la durée des cycles est maintenue constante pendant la cémentation.
5.- Procédé selon l'une des revendications 1 à 4, caractérisé en ce que l'atmosphère gazeuse est constituée exclusivement d'un gaz inerte, notamment de l'azote et d'un gaz contenant du carbone ou bien de plusieurs gas contenant du carbone notamment de propane.
EP82110429A 1981-11-20 1982-11-11 Procédé de cémentation de pièces métalliques Expired EP0080124B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3146042 1981-11-20
DE19813146042 DE3146042A1 (de) 1981-11-20 1981-11-20 Verfahren zum einsatzhaerten metallischer werkstuecke

Publications (3)

Publication Number Publication Date
EP0080124A2 EP0080124A2 (fr) 1983-06-01
EP0080124A3 EP0080124A3 (en) 1984-08-22
EP0080124B1 true EP0080124B1 (fr) 1986-09-24

Family

ID=6146826

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82110429A Expired EP0080124B1 (fr) 1981-11-20 1982-11-11 Procédé de cémentation de pièces métalliques

Country Status (9)

Country Link
EP (1) EP0080124B1 (fr)
AT (1) AT373294B (fr)
AU (1) AU548340B2 (fr)
BR (1) BR8206714A (fr)
DE (2) DE3146042A1 (fr)
ES (1) ES8307921A1 (fr)
GR (1) GR77758B (fr)
NO (1) NO823887L (fr)
ZA (1) ZA828553B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007047074A1 (de) * 2007-10-01 2009-04-02 Robert Bosch Gmbh Verfahren zur Aufkohlung von Werkstücken sowie Verwendung
CN103556106A (zh) * 2013-10-30 2014-02-05 西安航空动力股份有限公司 一种1Cr17Ni2合金材料高温真空渗碳层的制备方法

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2656003B1 (fr) * 1989-12-14 1994-02-11 Michel Gantois Procede et installation de traitement thermique ou thermochimique d'un acier, permettant le controle de l'enrichissement en carbone de la zone superficielle.
US5139584A (en) * 1989-07-13 1992-08-18 Solo Fours Industriels Sa Carburization process
FR2681332B1 (fr) * 1991-09-13 1994-06-10 Innovatique Sa Procede et dispositif de cementation d'un acier dans une atmosphere a basse pression.
US6547888B1 (en) 2000-01-28 2003-04-15 Swagelok Company Modified low temperature case hardening processes
ATE274073T1 (de) * 2000-05-24 2004-09-15 Ipsen Int Gmbh Verfahren und vorrichtung zur wärmebehandlung metallischer werkstücke
FR2821362B1 (fr) * 2001-02-23 2003-06-13 Etudes Const Mecaniques Procede de cementation basse pression
DE10221605A1 (de) * 2002-05-15 2003-12-04 Linde Ag Verfahren und Vorrichtung zur Wärmebehandlung metallischer Werkstücke
EP2541176A3 (fr) * 2005-11-23 2014-09-24 Surface Combustion, Inc. Système de distribution de fluide d'un four atmosphérique pour le traitement de surface d' articles métalliques
DE102007038983A1 (de) * 2007-08-17 2009-02-19 Robert Bosch Gmbh Verfahren zur Herstellung einer Verschleißschutzschicht an einem weichmagnetischen Bauteil
EP2627795A1 (fr) 2010-10-11 2013-08-21 Ipsen International GmbH Procédé et dispositif de carburation et carbonitruration de matériaux métalliques

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0049531A1 (fr) * 1980-10-08 1982-04-14 Linde Aktiengesellschaft Procédé pour la cémentation gazeuse de pièces en acier

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE618026C (de) * 1932-08-28 1935-08-30 Ewald Hanus Verfahren zum Zementieren von Eisen und Stahl
FR835931A (fr) * 1938-03-30 1939-01-05 Procédé pour la cémentation gazeuse de pièces en acier
FR1164640A (fr) * 1955-12-06 1958-10-13 Elino Ind Ofenbau Carl Hanf & Procédé pour la cémentation, la nitruration et la carbonitruration de pièces en acier
DE2851982A1 (de) * 1978-12-01 1980-06-12 Degussa Verfahren zum steuern von aufkohlungsprozessen im unterdruckbereich
DE3038078A1 (de) * 1980-10-08 1982-05-06 Linde Ag, 6200 Wiesbaden Verfahren und vorrichtung zum aufkohlen metallischer werkstuecke

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0049531A1 (fr) * 1980-10-08 1982-04-14 Linde Aktiengesellschaft Procédé pour la cémentation gazeuse de pièces en acier

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Lueger, Lexikon der Hüttentechnik, p. 150-152 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007047074A1 (de) * 2007-10-01 2009-04-02 Robert Bosch Gmbh Verfahren zur Aufkohlung von Werkstücken sowie Verwendung
CN103556106A (zh) * 2013-10-30 2014-02-05 西安航空动力股份有限公司 一种1Cr17Ni2合金材料高温真空渗碳层的制备方法
CN103556106B (zh) * 2013-10-30 2015-10-28 西安航空动力股份有限公司 一种1Cr17Ni2合金材料高温真空渗碳层的制备方法

Also Published As

Publication number Publication date
AT373294B (de) 1984-01-10
NO823887L (no) 1983-05-24
ZA828553B (en) 1983-09-28
GR77758B (fr) 1984-09-25
AU548340B2 (en) 1985-12-05
DE3146042A1 (de) 1983-05-26
AU9040182A (en) 1983-05-26
EP0080124A3 (en) 1984-08-22
ATA84282A (de) 1983-05-15
EP0080124A2 (fr) 1983-06-01
DE3273483D1 (en) 1986-10-30
ES517532A0 (es) 1983-08-01
ES8307921A1 (es) 1983-08-01
BR8206714A (pt) 1983-10-04

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