WO1993017146A1 - Procede de traitement thermochimique-thermique d'aciers de cementation - Google Patents

Procede de traitement thermochimique-thermique d'aciers de cementation Download PDF

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Publication number
WO1993017146A1
WO1993017146A1 PCT/EP1992/002951 EP9202951W WO9317146A1 WO 1993017146 A1 WO1993017146 A1 WO 1993017146A1 EP 9202951 W EP9202951 W EP 9202951W WO 9317146 A1 WO9317146 A1 WO 9317146A1
Authority
WO
WIPO (PCT)
Prior art keywords
temperature
process step
carbon
followed
hardening
Prior art date
Application number
PCT/EP1992/002951
Other languages
German (de)
English (en)
Inventor
Wenzel Bina
Dieter Eckert
Werner Kreiss
Original Assignee
Ina Wälzlager Schaeffler Kg
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 Ina Wälzlager Schaeffler Kg filed Critical Ina Wälzlager Schaeffler Kg
Priority to EP93901704A priority Critical patent/EP0627019B1/fr
Priority to DE59209268T priority patent/DE59209268D1/de
Publication of WO1993017146A1 publication Critical patent/WO1993017146A1/fr

Links

Classifications

    • 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
    • C21D1/78—Combined heat-treatments not provided for above
    • 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
    • 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
    • C23C8/40—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 liquids, e.g. salt baths, liquid suspensions
    • C23C8/52—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 liquids, e.g. salt baths, liquid suspensions more than one element being applied in one step
    • C23C8/54—Carbo-nitriding
    • C23C8/56—Carbo-nitriding of ferrous surfaces

Definitions

  • the invention relates to a method for the thermochemical treatment of case-hardening steels, in which an edge zone of a workpiece, in particular cup tappets, roller bearing parts, gear and coupling elements, is enriched with carbon and nitrogen and then subjected to a martensitic hardening.
  • One such method is carbonitriding for treating a workpiece in the austenitic state with the purpose of enriching the surface layer with carbon and with nitrogen, both elements subsequently being in solid solution in the austenite. Following this treatment, quenching is generally carried out immediately in order to achieve hardening. Carbonitriding improves the surface hardness and wear resistance of the structural parts (technology of heat treatment of steel, p. 169 ff, VEB German publishing house for basic material industry, Leipzig 1986).
  • the workpieces treated according to this method have improved properties with regard to wear resistance, but these are not sufficient in every application for components which are subject to high tribological stress, such as the contact surfaces of tappets in the valve train of an internal combustion engine.
  • these components have to be ground so that the highly enriched, wear-resistant outermost surface layer is at least partially ground away in the course of this cutting shaping.
  • Nitro carburizing is a thermochemical method for enriching the edge layer of a workpiece with nitrogen and carbon to form a connection layer, a diffusion layer enriched with nitrogen being formed above the connection layer.
  • a prerequisite for the functionality of nitrocarburized parts is a corresponding supporting effect of the diffusion layer under the naturally more or less brittle connection layer.
  • connection layer tends to plastic deformation under high tribological stresses, such as foreign bodies in the oil circuit of an internal combustion engine, and as a result can damage the connection layer.
  • the object of the present invention is to create a thermochemical-thermal treatment method which ensures sufficient wear resistance in the case of components which are subject to high tribological stress.
  • a first process step consists of carbonitriding at a temperature of 780 to 1050 ° C., with carburization and nitriding to 0.4 to 0.9 percent by weight of carbon and 0.1 to 0.8, preferably 0, 3 to 0.7 weight percent nitrogen is set.
  • the high temperatures ensure that the austenite in the peripheral zone has a correspondingly high solvency for both carbon and nitrogen.
  • the enrichment of the diffusion elements nitrogen and carbon has to be carried out in such a way that their solubility in austenite is not exceeded, ie the carbon potential in the atmosphere is to be adjusted in accordance with the SE line in the iron-carbon diagram. The same applies to the nitrogen supply according to the iron-nitrogen status diagram.
  • the holding time during carbonitriding which is one to four hours may depend on the desired hardening depth, the upper limit of which may be one millimeter.
  • the chemical composition of the edge zone is achieved by diffusion of carbon and nitrogen at the temperatures mentioned in a known manner using a working gas which contains both carbon-donating components and nitrogen-donating components.
  • the second step in the process of carbonitriding is rapid subcooling of the hardened material by quenching in suitable media.
  • the quenching should take place, for example in an oil bath, at temperatures well below the martensite starting point of the edge zone.
  • the diffusion process of the iron companions nitrogen and carbon is interrupted and the cementite precipitation at the austenite grain boundaries is suppressed, and a structure is formed which is composed of martensite containing carbon and nitrogen and a residual austenite content of up to 50%.
  • the surface hardness is between 65 and 55 Rockwell hardness.
  • the aim of the simultaneous enrichment with carbon and nitrogen in the present case is to increase the tempering resistance of said case hardening steel against case hardening.
  • the third step in the process of carbonitriding is followed by a heat treatment in which the material is tempered at 520 to 650 °, ie 20 to 40 ° C above the subsequent nitrocarburizing temperature.
  • the heating rate is between 10 to 30 ° per minute and the holding time is about 1 to 2 hours.
  • the fourth process step is followed by cooling to room temperature, the cooling rate being selected so that no new stresses are generated in the component as a result of the cooling. Tempering at a temperature of 20 to 40 ° C. above the nitro carburizing temperature means that the structural state set by carbonitriding in the edge region of the workpiece no longer changes during the subsequent nitro carburizing due to temperature influences.
  • the nitro carburizing follows as the sixth step of the method according to the invention.
  • the goal is to build a closed connection layer up to 20 ⁇ m thick.
  • the ground parts are treated at temperatures from 500 to 620 ° C for 60 to 150 minutes.
  • Nitro carburizing takes place in a gas mixture of ammonia, carbon dioxide, nitrogen and endogas or exogas.
  • the cooling of the nitrided material as the last step of the process can take place under protective gas in the furnace or by quenching in oil.
  • the nitro carburizing is carried out at a temperature of 530 to 570 ° C.
  • these temperatures are below the eutectoid temperature and, on the other hand, they are high enough to build up the connection layer with a sufficiently high growth rate.
  • the nitro carburizing can also be carried out in plasma or in a salt bath.
  • case hardening takes place at a temperature of 780 to 1050 ° C. with a carburization of the peripheral zone of 0.4 to 0.9 percent by weight of carbon with a holding time of 1 to 4 hours .
  • the subsequent method steps remain the same as described in the characterizing part of claim 1.
  • thermochemical-thermal treatment gives the material a high degree of wear resistance and load-bearing capacity, since the diffusion layer lying underneath the supporting layer has a significantly improved supporting effect, so that the connecting layer does not become plastically deformed even under the highest tribological stresses the underlying diffusion layer can be damaged.
  • Figure 1 shows the individual process steps of the method according to the invention as a function of time and temperature
  • Figure 2 shows a cross section in the region of the functional surface.
  • the carbonitriding takes place at a temperature of 780 to 1050 ° C.
  • the edge zone is carburized and nitrided within 1 to 4 hours.
  • This phase is followed by a phase 2, in which the structure is quenched to a temperature well below the martensite starting point of the edge zone.
  • the material is left at 20 to 40 ° C. above the nitro carburizing temperature for 1 to 2 hours.
  • the material is cooled under an oven or protective gas atmosphere before, as shown in dashed lines, the parts are subjected to an exciting shaping process in a fifth phase in order to bring them to their finished part dimensions.
  • a closed connecting layer 2 to 20 ⁇ m, preferably 6 to 12 ⁇ m thick is built up within 60 to 150 minutes.
  • the ground parts are used for this Treated temperatures from 500 to 620 ° C in a gas mixture of ammonia, carbon dioxide, nitrogen and endogas or exogas.
  • the last phase 7 is followed by cooling of the nitro carburized material under protective gas in the oven or by quenching in oil or aqueous media. Points that are not subject to wear and tear can be reworked.
  • FIG. 2 schematically shows the layer structure of the edge zone of a part which is treated by the method according to the invention.
  • the size relationships between the connection layer and the diffusion layer are such that the thickness of the connection layer is up to 20 ⁇ m, while the diffusion layer can have a thickness of several tenths of a millimeter.
  • the starting material 10 adjoins the diffusion layer 9.
  • the supporting effect of the diffusion layer located under the connecting layer is significantly improved by carbonitriding and tempering compared to an only nitro-carburized part.

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)
  • Heat Treatment Of Articles (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

L'invention concerne un procédé de traitement thermochimique/thermique d'aciers de cémentation selon lequel la zone marginale d'une pièce à usiner, notamment des coulisseaux de boisseau, des pièces de paliers à roulement, des éléments d'engrenage et d'accouplement, peut être enrichie avec du carbone et de l'azote, puis être soumise à une trempe martensitique. Le procédé objet de l'invention se caractérise par le fait qu'une carbonitruration (1) s'effectue à une température comprise entre 780 et 1050 °C, avec une cémentation et une nitruration de la zone marginale de 0,4 à 0,9 % en poids de carbone et de 0,1 à 0,8 % en poids d'azote pendant une période de 1 à 4 heures; que la carbonitruration est suivie d'une trempe (2) ramenée à une température nettement inférieure au point de départ martensitique de la zone marginale; que cette opération est suivie à son tour d'un processus de revenu (3) à une température supérieure de 20 à 40 °C à une température de nitrocarburation, avec une vitesse de chauffe comprise entre 10 à 30 °C par minute et pendant une période d'1 à 2 heures, et d'un refroidissement (4) à température ambiante; que cette opération est ensuite suivie d'un usinage par enlèvement de copeaux de la pièce à usiner, suivi à son tour d'une nitrocarburation (6) à une température comprise entre 500 et 620 °C, pendant une période de 60 à 150 minutes, et d'un refroidissement (7) jusqu'à la température ambiante. Le procédé objet de l'invention confère au matériau une résistance à l'usure et une force portante élevées, même lors de contraintes tribologiques extrêmement fortes.
PCT/EP1992/002951 1992-02-25 1992-12-18 Procede de traitement thermochimique-thermique d'aciers de cementation WO1993017146A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP93901704A EP0627019B1 (fr) 1992-02-25 1992-12-18 Procede de traitement thermochimique-thermique d'aciers de cementation
DE59209268T DE59209268D1 (de) 1992-02-25 1992-12-18 Verfahren zur thermochemisch-thermischen behandlung von einsatzstählen

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4205647.0 1992-02-25
DE4205647A DE4205647C2 (de) 1992-02-25 1992-02-25 Verfahren zur thermochemisch-thermischen Behandlung von Einsatzstählen

Publications (1)

Publication Number Publication Date
WO1993017146A1 true WO1993017146A1 (fr) 1993-09-02

Family

ID=6452467

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1992/002951 WO1993017146A1 (fr) 1992-02-25 1992-12-18 Procede de traitement thermochimique-thermique d'aciers de cementation

Country Status (3)

Country Link
EP (1) EP0627019B1 (fr)
DE (2) DE4205647C2 (fr)
WO (1) WO1993017146A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2316097A (en) * 1996-08-13 1998-02-18 Tochigi Fuji Sangyo Kk Hardened structural steel containing cementite

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3326874B2 (ja) 1993-05-31 2002-09-24 日本精工株式会社 転がり軸受
DE4327440C2 (de) * 1993-08-14 1997-07-03 Schaeffler Waelzlager Kg Verfahren zur thermochemisch-thermischen Behandlung von Einsatzstählen, Vergütungsstählen und Wälzlagerstählen
DE4418245C2 (de) * 1993-08-14 2003-06-18 Ina Schaeffler Kg Verfahren zur thermochemisch-thermischen Behandlung einer Gleitfläche eines Nockens und/oder einer Gleitfläche eines Nockengegenläufers
JP3411637B2 (ja) * 1993-10-05 2003-06-03 本田技研工業株式会社 内燃機関用ロッカアームの製造方法
US5575064A (en) * 1994-12-06 1996-11-19 Honda Giken Kogyo Kabushiki Kaisha Process for producing rocker arm for internal combustion engine
US6224266B1 (en) * 1998-09-18 2001-05-01 Ntn Corporation Wheel bearing device
DE102004028221A1 (de) 2004-06-09 2005-12-29 Ina-Schaeffler Kg Hochbeanspruchtes Motorenbauteil
DE102004043550B4 (de) * 2004-09-09 2012-02-16 Schaeffler Technologies Gmbh & Co. Kg Verschleißfeste Beschichtung, ihre Verwendung und Verfahren zur Herstellung derselben
JP5898092B2 (ja) * 2010-12-13 2016-04-06 川崎重工業株式会社 駆動カム、その製造方法、及びエンジンの動弁装置
WO2014031052A1 (fr) 2012-08-21 2014-02-27 Aktiebolaget Skf Procédé de traitement thermique d'une pièce d'acier et pièce d'acier
DE102015204656A1 (de) * 2015-03-16 2016-09-22 Aktiebolaget Skf Schichtbildung für Wälzlagerkomponenten
SE1550958A1 (en) * 2015-07-03 2017-01-04 Scania Cv Ab A rocker arm and a rocker arm assembly
DE102018208283A1 (de) * 2018-05-25 2019-11-28 Robert Bosch Gmbh Verfahren zum Herstellen eines metallischen Bauteils
CN111945104A (zh) * 2020-08-17 2020-11-17 沈阳飞机工业（集团）有限公司 薄层氮碳共渗方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2283244A1 (fr) * 1973-12-08 1976-03-26 Bell Thomas Procede et dispositif de carbonitruration des metaux ferreux
EP0033403A1 (fr) * 1980-01-31 1981-08-12 Ford Motor Company Procédé de traitement de la surface d'articles en acier à haute teneur en carbone et articles en acier à haute teneur en carbone
FR2514035A1 (fr) * 1981-10-01 1983-04-08 Komatsu Mfg Co Ltd Procede de traitement thermique de durcissement de surface de l'acier, acier convenant pour ce traitement et acier traite obtenu

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU609771A1 (ru) * 1976-12-22 1978-05-10 Предприятие П/Я В-2302 Способ обработки стальных изделий
SE441933B (sv) * 1984-02-14 1985-11-18 Ibm Svenska Ab Uppkolnings- och vermebehandlingsprocess for en maskindel, exempelvis en tryckhammare
JP2779170B2 (ja) * 1988-07-25 1998-07-23 マツダ株式会社 浸炭焼入方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2283244A1 (fr) * 1973-12-08 1976-03-26 Bell Thomas Procede et dispositif de carbonitruration des metaux ferreux
EP0033403A1 (fr) * 1980-01-31 1981-08-12 Ford Motor Company Procédé de traitement de la surface d'articles en acier à haute teneur en carbone et articles en acier à haute teneur en carbone
FR2514035A1 (fr) * 1981-10-01 1983-04-08 Komatsu Mfg Co Ltd Procede de traitement thermique de durcissement de surface de l'acier, acier convenant pour ce traitement et acier traite obtenu

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2316097A (en) * 1996-08-13 1998-02-18 Tochigi Fuji Sangyo Kk Hardened structural steel containing cementite
GB2316097B (en) * 1996-08-13 1999-06-23 Tochigi Fuji Sangyo Kk Structural steel and structural steel member used under high surface pressure

Also Published As

Publication number Publication date
DE4205647C2 (de) 1996-08-01
EP0627019B1 (fr) 1998-04-01
DE4205647A1 (de) 1993-08-26
EP0627019A1 (fr) 1994-12-07
DE59209268D1 (de) 1998-05-07

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