EP0049531A1 - Procédé pour la cémentation gazeuse de pièces en acier - Google Patents

Procédé pour la cémentation gazeuse de pièces en acier Download PDF

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Publication number
EP0049531A1
EP0049531A1 EP81108035A EP81108035A EP0049531A1 EP 0049531 A1 EP0049531 A1 EP 0049531A1 EP 81108035 A EP81108035 A EP 81108035A EP 81108035 A EP81108035 A EP 81108035A EP 0049531 A1 EP0049531 A1 EP 0049531A1
Authority
EP
European Patent Office
Prior art keywords
pressure fluctuations
carbon
furnace
containing gas
gas
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
EP81108035A
Other languages
German (de)
English (en)
Other versions
EP0049531B1 (fr
Inventor
Karlheinz Längerich
Rüdiger Dr. Conrad
Wolfgang Dr. Danzer
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
Xaver Fendt and Co
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, Xaver Fendt and Co filed Critical Linde GmbH
Publication of EP0049531A1 publication Critical patent/EP0049531A1/fr
Application granted granted Critical
Publication of EP0049531B1 publication Critical patent/EP0049531B1/fr
Expired legal-status Critical Current

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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
    • 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

Definitions

  • the invention relates to a method for case hardening metallic workpieces, in which they are exposed to the action of a carbon-containing gas mixture in an oven at high temperatures.
  • Case hardening is a process for the heat treatment of metals in the presence of a carbon-containing or nitrogen-containing gas mixture, in which the surface layer of a metal workpiece is thermochemically treated with carbon and, if necessary, with nitrogen (carburizing or carbonitriding).
  • the heat treatment changes the chemical composition of the workpiece by diffusing carbon or nitrogen in or out.
  • the transport of the gaseous carburizing agent to the workpiece can be the rate-determining step of the carburizing process in the case of rapidly carburizing gas atmospheres.
  • a sufficiently quick transport to disadvantaged people is then necessary Workpiece surfaces no longer exist, which leads to insufficient carburization (e.g. in the case of gearwheels in the tooth base) or to soft spots.
  • the invention is therefore based on the object of specifying a method of the type described in the introduction, in which a uniform surface quality of all treated metallic workpieces is achieved by the heat treatment.
  • This object is achieved in that pressure fluctuations are generated in the gas mixture with a significantly shorter period compared to the duration of the heat treatment.
  • edge zone properties of the workpieces treated by the method according to the invention consequently improve since it is not necessary to add oxygen to remove the soot deposits.
  • the method according to the invention also shortens the entire carburization process, since a large carbon potential gradient is achieved between the workpiece surface and the workpiece core and this potential gradient also acts as a driving diffusion force.
  • the gas mixture is formed from at least two components, the pressure fluctuations being caused by pulsating addition of one component or by each because pulsating addition of several components into the furnace are generated.
  • This variant of the method is particularly suitable when the furnace atmosphere outside the furnace is formed from two or more components which are stored individually and mixed under excess pressure and input into the furnace.
  • each individual gas component can be mixed with the other components in a pulsating manner.
  • only one shut-off device is required, which can be operated automatically if necessary.
  • the pressure fluctuations are caused by pulsating addition of the inert carrier gas and / or the carbon- and / or nitrogen-containing gas Generated gas and / or the oxygen-containing gas. It is possible to choose the amplitude and frequency of the pressure fluctuations of the individual gas components differently.
  • the pressure fluctuations of the inert carrier gas can be dimensioned in such a way that a constant gas movement, which is dependent, among other things, on the furnace size, is brought about within the furnace, while the pressure fluctuations of the carbon-containing or nitrogen-containing gas are primarily aimed at the carbon or Provide sufficient nitrogen.
  • a hydrocarbon with more than one carbon atom is advantageously used as the carbon-containing gas in the process according to the invention.
  • Such hydrocarbons become unstable at the temperatures prevailing in the furnace and break down into several gaseous radicals. Because of the constant furnace volume, the decay is associated with an increase in pressure, which increases the more radicals are formed. This effect overlaps with the pressure fluctuations caused by the pulsating addition and amplifies these fluctuations.
  • pressure fluctuations are caused in the gas mixture to which the workpieces to be treated are exposed by opening and closing closures sealing the furnace chamber, for example explosion flaps.
  • the gas mixture in the furnace which is under pressure, is expanded to atmospheric pressure when it is opened and brought to pressure again after it has been closed.
  • the frequency of the pressure fluctuations is set as a function of the methane and / or hydrogen and / or soot content in the furnace atmosphere.
  • the method according to the invention not only achieves a faster carburization but also an improved carburization - in particular at geometrically unfavorable points.

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)
  • Making Paper Articles (AREA)
  • Threshing Machine Elements (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
EP81108035A 1980-10-08 1981-10-07 Procédé pour la cémentation gazeuse de pièces en acier Expired EP0049531B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3038082 1980-10-08
DE19803038082 DE3038082A1 (de) 1980-10-08 1980-10-08 Verfahren zum einsatzhaerten metallischer werkstuecke

Publications (2)

Publication Number Publication Date
EP0049531A1 true EP0049531A1 (fr) 1982-04-14
EP0049531B1 EP0049531B1 (fr) 1985-06-05

Family

ID=6113954

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81108035A Expired EP0049531B1 (fr) 1980-10-08 1981-10-07 Procédé pour la cémentation gazeuse de pièces en acier

Country Status (9)

Country Link
EP (1) EP0049531B1 (fr)
AT (1) ATA539780A (fr)
AU (1) AU542462B2 (fr)
BR (1) BR8102151A (fr)
DE (2) DE3038082A1 (fr)
DK (1) DK433081A (fr)
ES (1) ES8206641A1 (fr)
NO (1) NO813284L (fr)
ZA (1) ZA812499B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0080124A2 (fr) * 1981-11-20 1983-06-01 Linde Aktiengesellschaft Procédé de cémentation de pièces métalliques
FR2586259A1 (fr) * 1985-08-14 1987-02-20 Air Liquide Procede de cementation rapide dans un four continu

Citations (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
GB527081A (en) * 1938-03-30 1940-10-02 Renault Louis Improvements in or relating to gaseous cementation
DE1041067B (de) * 1955-12-06 1958-10-16 Elino Ind Ofenbau Carl Hanf & Verfahren zum Aufkohlen, Nitrieren oder Karbonitrieren von Stahlteilen
DE2624828A1 (de) * 1976-06-03 1977-12-15 Alco Standard Corp Verfahren und vorrichtung zur durchfuehrung einer waermebehandlung von werkstuecken
DE2851982A1 (de) * 1978-12-01 1980-06-12 Degussa Verfahren zum steuern von aufkohlungsprozessen im unterdruckbereich

Patent Citations (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
GB527081A (en) * 1938-03-30 1940-10-02 Renault Louis Improvements in or relating to gaseous cementation
DE1041067B (de) * 1955-12-06 1958-10-16 Elino Ind Ofenbau Carl Hanf & Verfahren zum Aufkohlen, Nitrieren oder Karbonitrieren von Stahlteilen
DE2624828A1 (de) * 1976-06-03 1977-12-15 Alco Standard Corp Verfahren und vorrichtung zur durchfuehrung einer waermebehandlung von werkstuecken
DE2851982A1 (de) * 1978-12-01 1980-06-12 Degussa Verfahren zum steuern von aufkohlungsprozessen im unterdruckbereich

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0080124A2 (fr) * 1981-11-20 1983-06-01 Linde Aktiengesellschaft Procédé de cémentation de pièces métalliques
EP0080124B1 (fr) * 1981-11-20 1986-09-24 Linde Aktiengesellschaft Procédé de cémentation de pièces métalliques
FR2586259A1 (fr) * 1985-08-14 1987-02-20 Air Liquide Procede de cementation rapide dans un four continu
EP0213991A1 (fr) * 1985-08-14 1987-03-11 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Procédé de cémentation rapide dans un four continu
US4769090A (en) * 1985-08-14 1988-09-06 L'air Liquide Rapid carburizing process in a continuous furnace

Also Published As

Publication number Publication date
ES505892A0 (es) 1982-09-01
NO813284L (no) 1982-04-13
DK433081A (da) 1982-04-09
AU6915581A (en) 1982-04-22
DE3038082A1 (de) 1982-05-06
AU542462B2 (en) 1985-02-21
EP0049531B1 (fr) 1985-06-05
DE3170867D1 (en) 1985-07-11
ES8206641A1 (es) 1982-09-01
BR8102151A (pt) 1982-08-17
ZA812499B (en) 1982-04-28
ATA539780A (de) 1982-04-15

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