WO2001055471A1 - Procede de carbonitruration d'aciers a haute teneur en carbone et fortement allies - Google Patents

Procede de carbonitruration d'aciers a haute teneur en carbone et fortement allies Download PDF

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Publication number
WO2001055471A1
WO2001055471A1 PCT/EP2001/000838 EP0100838W WO0155471A1 WO 2001055471 A1 WO2001055471 A1 WO 2001055471A1 EP 0100838 W EP0100838 W EP 0100838W WO 0155471 A1 WO0155471 A1 WO 0155471A1
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WO
WIPO (PCT)
Prior art keywords
carbon
carbonitriding
nitrogen
ammonia
propane
Prior art date
Application number
PCT/EP2001/000838
Other languages
German (de)
English (en)
Inventor
Hans-Peter Schmidt
Original Assignee
Messer Griesheim 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 Messer Griesheim Gmbh filed Critical Messer Griesheim Gmbh
Publication of WO2001055471A1 publication Critical patent/WO2001055471A1/fr

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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
    • C23C8/28—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 more than one element being applied in one step
    • C23C8/30—Carbo-nitriding
    • C23C8/32—Carbo-nitriding of ferrous surfaces

Definitions

  • the invention relates to a method for carbonitriding metallic workpieces by treating the workpieces in a carbonitriding atmosphere which is produced using a carbon-containing substance and ammonia
  • carbonitriding uses so-called "endogas” into which ammonia is added.
  • the ammonia content is in the range from 4 to 15% by volume of NH 3 .
  • Methane or Propane - It is also known to produce suitable gas mixtures using an oxygen-containing organic liquid, such as methanol.
  • the carburizing process is reversible when using endogas, so that there is the possibility of carburizing or decarburizing the materials.
  • Atomic nitrogen is required for nitriding.
  • the molecular nitrogen present in the endogas does not dissociate at the treatment temperatures sufficient in atomic nitrogen.
  • ammonia is added to the embroidery, which partially decomposes into atomic nitrogen at the high treatment temperatures, which can be absorbed by the metal.
  • the ammonia embroidery process is irreversible. The denitrification only takes place via the molecular nitrogen formation on the material surface:
  • the carbon level of the gas phase must be set to high values. This is only possible if a carbon activity of 1 (graphite) or greater is set.
  • Treatment temperatures of e.g. The levels of carbon dioxide and
  • Chromium-rich alloys (chromium content> 5% by weight) and tempered steels can therefore only be carburized or carbonitrided to a limited extent in endogas.
  • the invention is therefore based on the object of specifying a cost-effective method for producing a carbonitriding atmosphere for high-carbon and / or high-alloy steels, which prevents or reduces the formation of a covering layer or damage to the edge zone.
  • This object is achieved in that nitrogen, ammonia and propane are used as the carbon-containing substance to generate the carbonitriding atmosphere.
  • the dosage of the fresh gases nitrogen, propane and ammonia can be easily measured and adjusted, so that a predetermined, constant composition of the carbonitriding atmosphere and thus a defined and reproducible nitrogen and carburization can be achieved. Due to the comparatively low C0 2 content, the C0 2 emissions are also reduced in this process. In addition, operating costs can be saved by replacing endogas with the cheaper nitrogen.
  • the process according to the invention is particularly easy to reproduce if only propane is used as the carbon-containing substance to generate the carbonitriding atmosphere.
  • the water content of the carbonitriding atmosphere is preferably set to less than 0.1% by volume. This can be achieved by using a dry nitrogen / propane / ammonia mixture. As a result, the decarburizing component H 2 0 is avoided and a high carbon activity in the carbonitriding atmosphere is achieved.
  • the carbon dioxide content of the carbonitriding atmosphere is less than 0.1% by volume. Because even by avoiding the decarburizing component C0 2 we achieve a high carbon activity in the carbonitriding atmosphere.
  • a carbonitriding atmosphere which has between 8 and 15% by volume of hydrogen, between 5 and 8% by volume of methane and between 0.5 and 1.5% by volume of ammonia has proven to be particularly favorable for carbonitriding of high-carbon and high-alloy steels and contains a maximum of 1 vol .-% carbon monoxide.
  • Methane is formed by thermal decomposition of the propane used in the invention.
  • the contents of carbon dioxide and water in such a carbonitriding atmosphere are less than 0.1% by volume.
  • Tests on the carbonitriding of metal components made of hardenable, chromium and manganese steel were carried out on a retort furnace. Nitrogen and propane were used to create the carbonitriding atmosphere.
  • the flow rates of nitrogen, propane and ammonia were measured in each case using a flow meter and using a method which was lower than that used in the conventional method Endogas changed feed point metered.
  • the sample gas for the analysis of the furnace gas atmosphere that was established was pumped out via a sampling tube.
  • the reaction of the individual gas components resulted in contents of approx. 10% hydrogen, 6-7% methane, 1% residual ammonia and 0.5% carbon monoxide, so that the furnace exhaust gas burned with yellow-colored paint.
  • the contents of water and carbon dioxide were below the detection limit of the measuring device (less than 0.05%) in all tests.
  • the nitrogen concentration in the carburized alloy is defined by the stationary contents of hydrogen and residual ammonia in the furnace gas and by the treatment temperature. These concentrations can be measured with gas analyzers and used to calculate nitrogen activity (a N ).
  • the nitrogen activity (SN) is a direct measure of the expected nitrogen concentration (CN) in the alloy.
  • the correction factor ) takes into account all parameters that have a positive or negative influence on the solubility of nitrogen. It contains the alloy, gas and plant-specific influencing variables and must therefore be determined empirically.
  • the carbon concentration in the carburized alloy is defined by the stationary contents of hydrogen and methane in the furnace gas and by the treatment temperature. The methane forms during the thermal cracking of the propane and through reaction of the hydrogen resulting from the ammonia dissociation with carbon.
  • the carbon activity (a c ) is a direct measure of the expected carbon concentration (C c ) in the alloy.
  • the correction factor takes into account all parameters that affect the solubility of carbon.
  • the alloy, gas and plant-specific influencing variables are contained in the constant and must therefore also be determined empirically.
  • Table 4 lists the gas concentrations measured in the furnace chamber according to the invention (data in% by volume):
  • edge oxidation depth of the alloy elements such as silicon, manganese and chromium
  • the use of nitrogen / popan instead of endogas is also preferable for edge oxidation reasons.
  • a very low carbon monoxide content occurs in the treatment gas in the process according to the invention.
  • the carbon monoxide content is between 20 vol .-% and about 23 vol .-%.
  • the depletion depth of alloy elements and the resultant hem of fine-streaked periite can be reduced or avoided by the method according to the invention and the quality of the treated components can be improved.

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)

Abstract

On connaît des procédés de carbonitruration de pièces métalliques par traitement desdites pièces dans une atmosphère de carbonitruration produite à l'aide d'une part d'une substance à base de carbone et d'autre part d'ammoniac. L'invention vise, sur cette base, à mettre au point un procédé économique pour produire une atmosphère de carbonitruration pour des aciers à haute teneur en carbone et/ou fortement alliés, qui empêchent ou minimisent la formation d'une couche de couverture ou l'altération de la zone marginale. A cet effet, il est prévu pour la carbonitruration de pièces métalliques à base d'aciers à haute teneur en carbone et/ou fortement alliés, d'utiliser de l'azote, de l'ammoniac et du propane comme substance à base de carbone pour produire l'atmosphère de carbonitruration.
PCT/EP2001/000838 2000-01-27 2001-01-26 Procede de carbonitruration d'aciers a haute teneur en carbone et fortement allies WO2001055471A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2000103526 DE10003526A1 (de) 2000-01-27 2000-01-27 Verfahren zum Karbonitrieren von kohlenstoffreichen und hochlegierten Stählen
DE10003526.4 2000-01-27

Publications (1)

Publication Number Publication Date
WO2001055471A1 true WO2001055471A1 (fr) 2001-08-02

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2001/000838 WO2001055471A1 (fr) 2000-01-27 2001-01-26 Procede de carbonitruration d'aciers a haute teneur en carbone et fortement allies

Country Status (2)

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DE (1) DE10003526A1 (fr)
WO (1) WO2001055471A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2909100A1 (fr) * 2006-11-28 2008-05-30 Snr Roulements Sa Procede de renforcement d'une piece en acier riche en carbone par carbonitruration a basse pression.
WO2011098306A1 (fr) * 2010-02-15 2011-08-18 Robert Bosch Gmbh Procédé de carbonitruration d'au moins un élément dans une chambre de traitement

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10321414B4 (de) * 2003-05-13 2008-12-18 Robert Bosch Gmbh Verfahren zur Wärmebehandlung von metallischen Werkstücken in Kammeröfen
AT526716A3 (de) 2022-12-01 2024-07-15 Gottfried Poeckl Verfahren zum Nitrieren von Bauteilen

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1156180A (en) * 1966-01-21 1969-06-25 Bohumil Prenosil A Low Temperature Process for the Carbonitriding of Structural Steel and Cast Iron
US3663315A (en) * 1969-03-26 1972-05-16 Union Carbide Corp Gas carburization and carbonitriding
GB1441091A (en) * 1972-08-15 1976-06-30 Barkas Werke Veb Treatment of piston rods
US4035203A (en) * 1973-12-21 1977-07-12 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method for the heat-treatment of steel and for the control of said treatment
SU679643A1 (ru) * 1976-02-16 1979-08-15 Вологодский Политехнический Институт Газова среда дл низкотемпературной нитроцементации
SU730876A1 (ru) * 1977-06-01 1980-05-03 Предприятие П/Я М-5953 Способ химико-термической обработки изделий из быстрорежущих и инструментальных сталей
US4322255A (en) * 1979-01-15 1982-03-30 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Heat treatment of steel and method for monitoring the treatment
US4461656A (en) * 1983-03-15 1984-07-24 Ross John A Low temperature hardening of the surface of a ferrous metal workpiece in a fluidized bed furnace
US5626974A (en) * 1994-08-25 1997-05-06 Nsk Ltd. Rolling bearing for use under high temperature conditions

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2524006B1 (fr) * 1982-03-23 1985-10-11 Air Liquide Procede de durcissement superficiel de pieces metalliques
DE3718240C1 (de) * 1987-05-30 1988-01-14 Ewald Schwing Verfahren zur Waermebehandlung von metallischen Werkstuecken in einer gasdurchstroemten Wirbelschicht

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1156180A (en) * 1966-01-21 1969-06-25 Bohumil Prenosil A Low Temperature Process for the Carbonitriding of Structural Steel and Cast Iron
US3663315A (en) * 1969-03-26 1972-05-16 Union Carbide Corp Gas carburization and carbonitriding
GB1441091A (en) * 1972-08-15 1976-06-30 Barkas Werke Veb Treatment of piston rods
US4035203A (en) * 1973-12-21 1977-07-12 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method for the heat-treatment of steel and for the control of said treatment
SU679643A1 (ru) * 1976-02-16 1979-08-15 Вологодский Политехнический Институт Газова среда дл низкотемпературной нитроцементации
SU730876A1 (ru) * 1977-06-01 1980-05-03 Предприятие П/Я М-5953 Способ химико-термической обработки изделий из быстрорежущих и инструментальных сталей
US4322255A (en) * 1979-01-15 1982-03-30 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Heat treatment of steel and method for monitoring the treatment
US4461656A (en) * 1983-03-15 1984-07-24 Ross John A Low temperature hardening of the surface of a ferrous metal workpiece in a fluidized bed furnace
US5626974A (en) * 1994-08-25 1997-05-06 Nsk Ltd. Rolling bearing for use under high temperature conditions

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 198016, Derwent World Patents Index; Class M13, AN 1980-28662C, XP002166199 *
DATABASE WPI Section Ch Week 198051, Derwent World Patents Index; Class M13, AN 1980-91509C, XP002166200 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2909100A1 (fr) * 2006-11-28 2008-05-30 Snr Roulements Sa Procede de renforcement d'une piece en acier riche en carbone par carbonitruration a basse pression.
WO2011098306A1 (fr) * 2010-02-15 2011-08-18 Robert Bosch Gmbh Procédé de carbonitruration d'au moins un élément dans une chambre de traitement
US9399811B2 (en) 2010-02-15 2016-07-26 Robert Bosch Gmbh Method for carbonitriding at least one component in a treatment chamber

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Publication number Publication date
DE10003526A1 (de) 2001-08-09

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