EP0018263A1 - Verfahren zum Verchromen von Stahlgegenständen und mit einem Chromdiffusionsüberzug versehene Stahlgegenstände - Google Patents

Verfahren zum Verchromen von Stahlgegenständen und mit einem Chromdiffusionsüberzug versehene Stahlgegenstände Download PDF

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Publication number
EP0018263A1
EP0018263A1 EP80400451A EP80400451A EP0018263A1 EP 0018263 A1 EP0018263 A1 EP 0018263A1 EP 80400451 A EP80400451 A EP 80400451A EP 80400451 A EP80400451 A EP 80400451A EP 0018263 A1 EP0018263 A1 EP 0018263A1
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EP
European Patent Office
Prior art keywords
nitrogen
metal part
depth
chromium
chromized
Prior art date
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Granted
Application number
EP80400451A
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English (en)
French (fr)
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EP0018263B1 (de
Inventor
André Robert Faure
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Atto Confirmatorio E Ricognitivo Di Licenza Esclus
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Aubert and Duval SA
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Priority to AT80400451T priority Critical patent/ATE3883T1/de
Publication of EP0018263A1 publication Critical patent/EP0018263A1/de
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Publication of EP0018263B1 publication Critical patent/EP0018263B1/de
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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
    • C23C12/00—Solid state diffusion of at least one non-metal element other than silicon and at least one metal element or silicon into metallic material 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
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/02—Pretreatment of the material to be coated
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
    • Y10T428/12576—Boride, carbide or nitride component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771—Transition metal-base component
    • Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
    • Y10T428/12826—Group VIB metal-base component
    • Y10T428/12847—Cr-base component
    • Y10T428/12854—Next to Co-, Fe-, or Ni-base component

Definitions

  • the present invention relates to a method for chromizing metal parts such as steel parts, of the type in which chromium is diffused in order to obtain a surface layer of chromium and in which the chromium supply is obtained by gas phase decomposition of chromium halides, the decomposition of the halide and the diffusion of chromium in the steel being carried out simultaneously by heating the parts to temperatures not exceeding 1300 ° C., in the halide atmosphere, the actual chromizing operation being preceded by a surface nitrogen addition operation.
  • the actual chromization is known, for example, from the works of Doctor GALMICHE and from the ONERA patents n ° 1.012.401 and their two additions 60.539 and 60.686.
  • the object of the present invention is to propose a hard chromization process of the aforementioned type and making it possible to produce steel parts having a hard chromized surface layer comprising carbo-nitrides, a layer having a thickness greater than at least 20 microns, preferably 30 microns, and a fine grain undercoat with little or no decar burée.
  • This object is achieved by the fact that prior to the actual chromizing operation, the introduction of nitrogen into the surface layer of the metal part is made so that the nitrogenous surface layer has a content greater than 0.8 % nitrogen over a depth or thickness at least equal to 0.5 mm.
  • hard chromized layers comprising carbo-nitrides instead of separate carbides and / or separate nitrides, these layers being of a thickness greater than at least 20 microns and having a high resistance to wear.
  • the presence of nitrogen in the surface layers of the steel parts makes it possible to achieve a different balance of the chromium and carbon elements with respect to the base steel during the chromization reaction, this different balance thus allowing to obtain much deeper chromized surface layers without producing significantly decarburized undercoats and without enlarging the grain in undercoat.
  • the surface introduction of nitrogen can be carried out by heating the workpiece to a temperature between 400 and 800 ° C. and in any case at a temperature below the lower critical point of the treated steel, and for the periods between 12 and 150 hours in a nitrogen generating medium which, by way of example may consist of molten nitrous salts, ammonia or nitrogen gases, ionized or not.
  • nitrogenous surface layers previously containing more than 0.8% nitrogen over a depth at least equal to 0.5 mm.
  • nitrogenous surface layers are prepared having a nitrogen content of between 1 and 2% over a depth of 0.5 to 1.0 mm.
  • Such satisfactory nitrogenous layers can be obtained by treatment cycles in an ammonia atmosphere of 24 hours at 700 ° C or 90 hours at 560 ° C.
  • the chromium halide atmosphere conforms to the already known technique
  • the temperature and holding time parameters can be conformed to the already known technique, but they can also be modified according to the prior introduction of nitrogen; compared to what they would be on the same non "activated" steel according to the present invention.
  • the chromization temperatures can be reduced in order to limit the magnification of the grains of the undercoat.
  • the steel parts can preferably undergo a regenerative heat treatment in order to reduce the grain sizes and improve the resilience of the base steel.
  • the comparison drawing shows the comparison of the chromized layers obtained on the same steel grade 32 CDV 13 (AFNOR) by known chromization techniques without or with prior activation by nitrogen and in the three cases followed by a heat treatment of grain regeneration by heating under vacuum, quenching and tempering.
  • AFNOR chromization technique
  • FIG. 1 is a micro-hardness diagram showing for the steel grade 32 CDV 13 (AFNOR) three examples of chromized steel parts and, FIGS. 2 to 4 show micro-photos of the surface layer and of the adjacent underlay of these three examples of chromized steel parts, the enlargement factor being in all three cases of 200.
  • AFNOR steel grade 32 CDV 13
  • the hardness of different levels of the steel parts is indicated on the ordinate, hardness measured in Vickers points and on the abscissa the thickness or depth of the layers in microns from the surface of the part of steel considered.
  • the curve a in solid lines represents the hardness of a piece of steel in Vickers degrees as a function of the depth of the level considered.
  • This piece of steel, the transverse structure of which is illustrated in FIG. 2 has not been previously activated by nitrogen, but only one chromium-plating operation for 12 hours at 940 ° C.
  • the chromized surface layer 1 has a depth or thickness of 12 microns and has a Vickers hardness greater than 1,500 points and reaching more than 1,800 points.
  • a sub-layer 2 whose Vickers hardness decreases rapidly to a minimum value of 260 and then slowly rises to Vickers hardness at the heart of the hardness steel part which is of the order of 350 and is reached at a depth of 77 microns.
  • this sublayer or decarburization zone 2 is of the order of 65 microns which is more than 5 times the thickness of the chromized surface layer 1 and the minimum hardness of the sublayer 2 is only about 3/4 of the Vickers hardness at the heart of the steel part.
  • the decrease in the hardness of the underlay compared to that of the core of the steel part clearly shows the extent of the decarburized zone and the harmful influence of the inevitable carbon pumping during the known chromization operation. It can also be seen from FIG. 2 that the size of the grain in the sub-layer is significant (Afnor index 4).
  • Curve b of FIG. 1 shows the hardness of a piece of steel of the same aforementioned grade without activation with nitrogen, subjected to a chromization operation also for 12 hours, but at a higher temperature, namely 980 ° C.
  • This increase in temperature brings the depth of the chromized surface layer 1 to 16 microns, but on the other hand the corresponding structure illustrated in FIG. 3 shows an even larger and unfavorable grain size (Afnor index 3) than that of the structure.
  • the diagram of microhardness shows at the bottom of curve b between a depth of 16 microns and 85 microns (sublayer 2) an even deeper and more intense decarburization zone (minimum Vickers hardness 240 points) than that of the example in the curve a and of FIG. 2.
  • the Vickers hardness of the undercoat 2 is of the order of 2/3 of the Vickers hardness at the heart of the steel part and the undercoat 2 with its decarburized zone a a thickness at least four times greater than that of the chromized surface layer 1.
  • Curve c of FIG. 1 corresponds to a piece of steel having undergone prior activation by the surface introduction of nitrogen in accordance with the present invention (treatment cycle of 90 hours at 560 ° C.).
  • This curve c in FIG. 1 shows the Vickers hardness of a piece of steel of the same grade as the previous examples, but is obtained after the same chromization cycle as the example of curve a, that is 12 hours at 940 ° C.
  • the chromized layer 1 has a depth of 50 microns.
  • the structure; illustrated by FIG. 4 also shows the fineness of the grain obtained in the sub-layer 2 over a depth of 1 mm and the diagram of microduretures (FIG. 1) shows for curve c a much less thick decarburization zone (20 to 30 microns ) and less intense (minimum Vickers hardness around 330 points) than in the two previous examples.
  • the thickness of the decarburized zone is very small, is less than that of the chromized layer 1 and is only approximately equal to half that of said chromized layer 1.
  • the hardness of the decarburized zone of the underlayer 2 it is at least equal to about 95% of the hardness of the core of the steel piece.
  • the loss of hardness in the underlayment compared to the base steel at The core of the steel part is inside 25 Vickers points and affects a weakly decarburized area with a thickness of less than 25 microns.
  • grain fineness which is at least equal to or greater than the Afnor6 index (index 7) over a thickness at least equal to 0.5 mm (1 mm) .
  • carbon-containing steel intended for hard chromium plating has a surface layer containing at least 0.8% nitrogen over a depth greater than 0.5 mm. It has been found that to the extent that the nitrogen content of the surface layer before chromization exceeds 0.8% over a depth of 0.5 mm, there is found after said chromization in the sublayer a higher residual nitrogen content at 0.4% over a depth greater than 0.5 mm, this nitrogen content preventing significant decarburization and a significant enlargement of the grain of the undercoat.
  • the nitrogen content of the surface layer of the steel is, before chromization, greater than 0.8% over a depth greater than 0.5 mm, after said chromization is found in the chromized surface layer the presence of chromium carbonitrides with a nitrogen content greater than 2%.
  • the invention relates not only to the new hard chromization process, but also to the pieces of steel treated with nitrogen with a view to chromization as well as to the pieces of steel chromized according to the present process and having a chromized surface layer. hard with a depth of at least 20 microns and a Vickers hardness of at least 1200 points.

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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)
  • Heat Treatment Of Steel (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
EP80400451A 1979-04-20 1980-04-03 Verfahren zum Verchromen von Stahlgegenständen und mit einem Chromdiffusionsüberzug versehene Stahlgegenstände Expired EP0018263B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80400451T ATE3883T1 (de) 1979-04-20 1980-04-03 Verfahren zum verchromen von stahlgegenstaenden und mit einem chromdiffusionsueberzug versehene stahlgegenstaende.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7910094 1979-04-20
FR7910094A FR2454471A1 (fr) 1979-04-20 1979-04-20 Procede de chromisation de pieces metalliques telles que des pieces d'acier et pieces metalliques chromisees

Publications (2)

Publication Number Publication Date
EP0018263A1 true EP0018263A1 (de) 1980-10-29
EP0018263B1 EP0018263B1 (de) 1983-06-22

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EP80400451A Expired EP0018263B1 (de) 1979-04-20 1980-04-03 Verfahren zum Verchromen von Stahlgegenständen und mit einem Chromdiffusionsüberzug versehene Stahlgegenstände

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US (1) US4481264A (de)
EP (1) EP0018263B1 (de)
AT (1) ATE3883T1 (de)
DE (1) DE3063830D1 (de)
FR (1) FR2454471A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986007614A1 (en) * 1985-06-17 1986-12-31 Kabushiki Kaisha Toyota Chuo Kenkyusho Method of treating the surface of iron alloy materials
EP1904661A1 (de) * 2005-07-21 2008-04-02 Hard Technologies Pty Ltd Duplexoberflächenbehandlung von metallgegenständen

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4578319A (en) * 1984-05-08 1986-03-25 Toyo Kohan Co., Ltd. Surface treated steel sheet having an excellent weldability and its production method
JP2584217B2 (ja) * 1986-11-18 1997-02-26 株式会社豊田中央研究所 表面処理方法
US5123972A (en) * 1990-04-30 1992-06-23 Dana Corporation Hardened insert and brake shoe for backstopping clutch
SA05260056B1 (ar) 1991-03-08 2008-03-26 شيفرون فيليبس كيميكال كمبني ال بي جهاز لمعالجة الهيدروكربون hydrocarbon
US6274113B1 (en) 1994-01-04 2001-08-14 Chevron Phillips Chemical Company Lp Increasing production in hydrocarbon conversion processes
US6258256B1 (en) 1994-01-04 2001-07-10 Chevron Phillips Chemical Company Lp Cracking processes
US5575902A (en) * 1994-01-04 1996-11-19 Chevron Chemical Company Cracking processes
US6419986B1 (en) 1997-01-10 2002-07-16 Chevron Phillips Chemical Company Ip Method for removing reactive metal from a reactor system
US6197125B1 (en) * 1999-12-13 2001-03-06 Mcdermott Technology, Inc. Modification of diffusion coating grain structure by nitriding
CN115058684B (zh) * 2022-06-29 2024-02-09 中国航发动力股份有限公司 一种高碳工具钢铬硬化层的制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3205153A (en) * 1962-05-21 1965-09-07 Chandler Evans Inc Process and product of chrome plating nitrided steel
FR1410647A (fr) * 1964-10-05 1965-09-10 Formsprag Co Procédé de durcissement des surfaces frottantes et nouveaux produits industriels obtenus
US3256818A (en) * 1955-11-26 1966-06-21 Berghaus Bernhard Method of reducing barrel wear
FR95448E (fr) * 1967-06-27 1970-11-06 Ct Stephanois De Rech Mecaniqu Traitement de surface pour pieces mécaniques.
FR2031373A1 (en) * 1969-02-17 1970-11-20 Petignat Maurice Surface-hardening of oxidn resistant austen - itic steel parts
EP0010484A1 (de) * 1978-10-25 1980-04-30 Creusot-Loire Verbesserung der Inchromierung von Stahl in der Gasphase

Family Cites Families (11)

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US2437249A (en) * 1946-04-17 1948-03-09 Nitralloy Corp Method of nitriding
FR1012401A (fr) * 1949-08-05 1952-07-09 Onera (Off Nat Aerospatiale) Perfectionnements apportés aux procédés de formation d'alliages superficiels de diffusion, notamment de chrome
FR60539E (fr) * 1949-12-06 1954-11-09 Nat D Etudes & De Rech S Aeron Perfectionnements apportés aux procédés de formation d'alliages superficiels de diffusion, notamment de chrome
FR60686E (fr) * 1950-06-27 1954-11-22 Onera (Off Nat Aerospatiale) Perfectionnements apportés aux procédés de formation d'alliages superficiels de diffusion, notamment de chrome
US3152007A (en) * 1961-04-13 1964-10-06 Diamond Alkali Co Process for chromizing ferrous metal objects
US3222212A (en) * 1962-11-29 1965-12-07 Alloy Surfaces Co Inc Process for chromizing
US3282746A (en) * 1963-11-18 1966-11-01 Formsprag Co Method of hardening wear surfaces and product
US3414428A (en) * 1964-10-20 1968-12-03 Allied Chem Chromizing compositions and methods and continuous production of chromium halides for chromizing
FR1555534A (de) * 1967-06-27 1969-01-31
US3892597A (en) * 1972-04-13 1975-07-01 Midland Ross Corp Method of nitriding
US4042426A (en) * 1975-03-10 1977-08-16 National Steel Corporation Chromized steel substrate

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3256818A (en) * 1955-11-26 1966-06-21 Berghaus Bernhard Method of reducing barrel wear
US3205153A (en) * 1962-05-21 1965-09-07 Chandler Evans Inc Process and product of chrome plating nitrided steel
FR1410647A (fr) * 1964-10-05 1965-09-10 Formsprag Co Procédé de durcissement des surfaces frottantes et nouveaux produits industriels obtenus
FR95448E (fr) * 1967-06-27 1970-11-06 Ct Stephanois De Rech Mecaniqu Traitement de surface pour pieces mécaniques.
FR2031373A1 (en) * 1969-02-17 1970-11-20 Petignat Maurice Surface-hardening of oxidn resistant austen - itic steel parts
EP0010484A1 (de) * 1978-10-25 1980-04-30 Creusot-Loire Verbesserung der Inchromierung von Stahl in der Gasphase

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SOVIET INVENTIONS ILLUSTRATED, juin 1966, Derwent Publications Ltd., Metallurgy (7), page 8, Londres GB, & SU - A - 176 152 (YU.N. GRIBOEDOV), (17-06-1964). *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986007614A1 (en) * 1985-06-17 1986-12-31 Kabushiki Kaisha Toyota Chuo Kenkyusho Method of treating the surface of iron alloy materials
EP1904661A1 (de) * 2005-07-21 2008-04-02 Hard Technologies Pty Ltd Duplexoberflächenbehandlung von metallgegenständen
EP1904661A4 (de) * 2005-07-21 2010-12-29 Hard Technologies Pty Ltd Duplexoberflächenbehandlung von metallgegenständen
US8317926B2 (en) 2005-07-21 2012-11-27 Hard Technologies Pty Ltd. Duplex surface treatment of metal objects

Also Published As

Publication number Publication date
FR2454471A1 (fr) 1980-11-14
FR2454471B1 (de) 1983-12-23
US4481264A (en) 1984-11-06
EP0018263B1 (de) 1983-06-22
DE3063830D1 (en) 1983-07-28
ATE3883T1 (de) 1983-07-15

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