EP0049532A1 - Procédé pour la cémentation et pour le traitement thermique de pièces en acier sans modification de la teneur en carbone - Google Patents

Procédé pour la cémentation et pour le traitement thermique de pièces en acier sans modification de la teneur en carbone Download PDF

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Publication number
EP0049532A1
EP0049532A1 EP81108036A EP81108036A EP0049532A1 EP 0049532 A1 EP0049532 A1 EP 0049532A1 EP 81108036 A EP81108036 A EP 81108036A EP 81108036 A EP81108036 A EP 81108036A EP 0049532 A1 EP0049532 A1 EP 0049532A1
Authority
EP
European Patent Office
Prior art keywords
organic liquid
addition
carbon
furnace
gas mixture
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
EP81108036A
Other languages
German (de)
English (en)
Other versions
EP0049532B1 (fr
Inventor
Reinhard Strigl
Thomas Reverchon
Alexander Jurmann
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
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
Publication of EP0049532A1 publication Critical patent/EP0049532A1/fr
Application granted granted Critical
Publication of EP0049532B1 publication Critical patent/EP0049532B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • 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
    • 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 carburizing and carbon-neutral annealing of workpieces which are exposed in a furnace at high temperatures to the action of a gas mixture formed from an organic liquid and other components.
  • the invention is therefore based on the object of developing a method of the type specified at the outset, with which a rapid carburizing or carbon-neutral annealing of metal parts is possible in an economical manner.
  • This object is achieved in that the organic liquid is pulsed during the action of the gas mixture, the workpieces are added to the other components before they are introduced into the furnace and / or the gas mixture.
  • a large carbon potential gradient between the workpiece surface and the core of the workpiece can be achieved by the pulsating addition of the organic liquid compared to previous methods.
  • a large carbon potential gradient acts as an additional, driving diffusion force, so that the pulsating entry of the organic liquid allows the carbon to penetrate rapidly into the workpiece to be treated.
  • the pulsating admixing is such that at least the organic liquid is introduced into the furnace in numerous phases during the carburization or the carbon-neutral annealing. In these phases, the carbon content of the gas mixture increases to a certain level, while it decreases in the periods between the introduction phases, since no organic liquid is added.
  • one of the other components is an inert carrier gas. If this gas is introduced in a pulsating manner, pressure fluctuations are caused in the furnace. Their amplitude and frequency can now be determined by suitable selection of the time and the duration of a phase in which gas is introduced, so that a constant movement of the furnace atmosphere is the result . This ensures that the gas mixture is evenly routed to all points on a workpiece, including geometrically unfavorable points or dead spaces within a bed, and a homogeneous gas mixture is set in the entire furnace. Insufficient carburizing of disadvantaged workpiece surfaces or carburizing or excessive carburizing of favored workpiece surfaces is thus avoided.
  • one of the other components can also be a hydrocarbon.
  • the addition of hydrocarbons is common during the carburization by means of organic liquids, as no sufficient A can be ufkohlungs Koch obtained with an organic liquid, as a rule. With. For example, methanol as an organic liquid only achieves a carbonation level of 0.5 to 0.6%.
  • the addition of hydrocarbons does not only allow one Your higher carbonation level, but also better regulation of that level.
  • the pulsating addition of hydrocarbons leads to a further essential advantage: the addition of the hydrocarbons can be selected so that the pressure fluctuations caused by the pulsating addition of the organic liquid are increased, the transfer of carbon into the metal is accelerated and so the carburizing speed is further increased. For this purpose, it is advantageous to adapt the rate of addition for the hydrocarbons to that of adding the organic liquid.
  • the organic liquid is therefore an alcohol, in particular methanol, and among the other components are an inert carrier gas, in particular nitrogen and a gaseous hydrocarbon, in particular a hydrocarbon with more than one carbon atom, or a further organic liquid such as acetone, Contain isopropanol, ethyl acetate.
  • Hydrocarbons with more than one carbon atom break down into several radicals at the temperatures in the furnace. This effect leads to an additional pressure increase in the furnace and thus to a further acceleration of the carbon transfer.
  • the duration of the addition of the carbon-containing components is short compared to the period between the end of one addition and the start of the next addition.
  • the duration of the addition is 1 sec. To 30 min., Preferably 10 to 60 sec.
  • the period between the end of one addition and the start of the next addition is 10 sec. To 60 min., Preferably 20 to 300 sec.
  • the methane and / or carbon dioxide and / or hydrogen and / or carbon monoxide content and / or the dew point and / or the oxygen potential in the gas mixture is continuously measured, the measured variables are fed to a control unit and the duration and time of the addition of the carbon-containing components Comparison of the measured variables with a respectively predefined setpoint depending on the difference between the setpoint and the measured variable is automatically regulated.
  • a gas mixture composition typical of conventional processes had a content of approximately 20% carbon monoxide, 40% hydrogen, 2 to 5% hydrocarbon gas and nitrogen.
  • the carbon monoxide content is between 5 and 30%, on average around 12 to 15%, that is below the conventional value.
  • the hydrogen content is 10 to 40%, this composition changing depending on the pulsation.
  • the proportion of hydrocarbons is then 2 to 10%.
  • the duration of the carburization is calculated from the point in time at which the furnace has reached the carburizing temperature of 940 ° C.
  • a comparison of the two experiments shows the advantages of the method according to the invention, according to which the consumption of methanol and the duration of the carburization are less or shorter than the conventional method.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
EP81108036A 1980-10-08 1981-10-07 Procédé pour la cémentation et pour le traitement thermique de pièces en acier sans modification de la teneur en carbone Expired EP0049532B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19803038081 DE3038081A1 (de) 1980-10-08 1980-10-08 Verfahren zum aufkohlen und kohlungsneutralen gluehen von werkstuecken
DE3038081 1980-10-08

Publications (2)

Publication Number Publication Date
EP0049532A1 true EP0049532A1 (fr) 1982-04-14
EP0049532B1 EP0049532B1 (fr) 1985-02-13

Family

ID=6113953

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81108036A Expired EP0049532B1 (fr) 1980-10-08 1981-10-07 Procédé pour la cémentation et pour le traitement thermique de pièces en acier sans modification de la teneur en carbone

Country Status (6)

Country Link
EP (1) EP0049532B1 (fr)
AT (1) AT369038B (fr)
AU (1) AU543040B2 (fr)
BR (1) BR8106481A (fr)
DE (2) DE3038081A1 (fr)
ZA (1) ZA816970B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2586259A1 (fr) * 1985-08-14 1987-02-20 Air Liquide Procede de cementation rapide dans un four continu

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3110329A1 (de) * 1981-03-17 1982-09-30 Brown, Boveri & Cie Ag, 6800 Mannheim Verfahren zur gasaufkohlung
DE3436267A1 (de) * 1984-10-03 1986-05-15 Process-Electronic Analyse- und Regelgeräte GmbH, 7336 Uhingen Verfahren zum regeln des kohlenstoffpegels in einem gasaufkohlungsofen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB527081A (en) * 1938-03-30 1940-10-02 Renault Louis Improvements in or relating to gaseous cementation
CH404338A (de) * 1960-06-17 1965-12-15 Maag Zahnraeder & Maschinen Ag Verfahren zum regelbaren Aufkohlen der Oberflächenschicht von Werkstücken aus Stahl

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1157164A (fr) * 1956-08-04 1958-05-27 Renault Procédé de préparation d'un mélange d'azote et de vapeur de produits organiques pour réaliser une atmosphère de traitement thermique

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB527081A (en) * 1938-03-30 1940-10-02 Renault Louis Improvements in or relating to gaseous cementation
CH404338A (de) * 1960-06-17 1965-12-15 Maag Zahnraeder & Maschinen Ag Verfahren zum regelbaren Aufkohlen der Oberflächenschicht von Werkstücken aus Stahl

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Harterei-Technische Mitteilungen, Band 35, Nr. 5, 1980, seiten 230-237 Munchen, DE. U. WYSS et al.: "Grundsatzliche Voraussetzungen fur die Verringerung der Gasverbrauches bei der Geregelten Gasaufkohlung" * Insgesamt * *
Metals Handbook, 8. Auflage, Band 2, Ausg. American Society for Metals, 1964, seiten 85,86 "Heat Treating, Cleaning and Finishing" * seiten 85,86, "Orsat Analyzer" * *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
DE3168921D1 (en) 1985-03-28
DE3038081A1 (de) 1982-05-06
ZA816970B (en) 1982-09-29
ATA84081A (de) 1982-04-15
AU7609381A (en) 1982-04-22
BR8106481A (pt) 1982-06-22
AU543040B2 (en) 1985-03-28
EP0049532B1 (fr) 1985-02-13
AT369038B (de) 1982-11-25

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