EP0248431B1 - Verfahren zur Herstellung von äusseren Decksschichten an den hitzebeständigen sowie korrosionsfesten insbesondere austenitischen Stählen - Google Patents

Verfahren zur Herstellung von äusseren Decksschichten an den hitzebeständigen sowie korrosionsfesten insbesondere austenitischen Stählen Download PDF

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Publication number
EP0248431B1
EP0248431B1 EP19870108108 EP87108108A EP0248431B1 EP 0248431 B1 EP0248431 B1 EP 0248431B1 EP 19870108108 EP19870108108 EP 19870108108 EP 87108108 A EP87108108 A EP 87108108A EP 0248431 B1 EP0248431 B1 EP 0248431B1
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EP
European Patent Office
Prior art keywords
heat
corrosion resistant
layer
coating layers
outer coating
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.)
Expired - Lifetime
Application number
EP19870108108
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0248431A3 (en
EP0248431A2 (de
Inventor
Czeslaw Janczur
Janusz Szelc
Stanislaw Dr. Ing. Mech. Rog
Boleslaw Doz. Dr.-Ing. Mech. Stolarski
Zygmunt Dipl.-Ing. Mech. Szolucha
Adam Kuklewicz
Ryszard Dr. Ing. Mech. Baran
Wieslaw Dipl.-Ing. Mech. Malarz
Tadeusz Dipl.-Ing. Chem. Mysliwy
Jerzy Dipl.-Ing. Mech. Pasich
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.)
Fabryka Samochodow Malolitrazowych "Polmo"
Politechnika Krakowska
Original Assignee
Fabryka Samochodow Malolitrazowych "Polmo"
Politechnika Krakowska
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 Fabryka Samochodow Malolitrazowych "Polmo", Politechnika Krakowska filed Critical Fabryka Samochodow Malolitrazowych "Polmo"
Publication of EP0248431A2 publication Critical patent/EP0248431A2/de
Publication of EP0248431A3 publication Critical patent/EP0248431A3/de
Application granted granted Critical
Publication of EP0248431B1 publication Critical patent/EP0248431B1/de
Anticipated expiration legal-status Critical
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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
    • C23C8/02—Pretreatment of the material to be coated

Definitions

  • the invention relates to a method for producing a diffusion cover layer with increased physico-chemical properties, which is obtained by a chemical-thermal process in a gas atmosphere by nitriding, on elements made of heat-resistant steel or corrosion-resistant steel.
  • the invention relates in particular to steel with an austenitic structure.
  • these steels passivate on the surface with an oxide layer, especially chromium oxide.
  • the passivation can take place both at the outside temperatures and during the thermal-chemical treatment, e.g. even under the conditions of trace wetting of the gas atmosphere of the dissociated ammonia.
  • This oxide layer especially that of chromium oxide, is very passive and diffusion-impermeable.
  • the previously known methods for the production of outer cover layers on this type of steel consist in carrying out the depassivation of the steel surfaces, which further enable an effective implementation of gas nitriding.
  • the surfaces are to be de-passivated mechanically, e.g. by blasting, electromechanically in baths or by chemical decomposition of the oxide layer with the de-passivators introduced into the gas atmosphere of the process.
  • the depassivators are added when nitriding in the gas atmosphere at the beginning of the process.
  • Halide compounds such as HF, HBr or NH ,Cl are mostly used.
  • Chemical Abstracts Part 85, No. 4/79, p.229, abstract No. 501920q describes a process in which trichlorethylene is used as a depassivator.
  • the trichlorethylene in the amount of 3% in the 50% endothermic gases and 50% NH3 gas atmosphere is supplied during the first 5 minutes of the process.
  • the nitriding is carried out at a temperature of 570 ° C for one hour.
  • Trichlorethylene is subject to pyrolysis to chlorine, which removes the chromium oxides from the steel surface.
  • the compounds that occur particularly in the gas atmosphere are characterized by a high level of toxicity, which determines the technical and ecological applicability of the process.
  • the depassivators introduced into the gas atmosphere also cause the depassivation of the inner surfaces of the system, especially the retort in which the process takes place.
  • the method for sulfonitriding is also known, in which the addition of sulfur vapors to the atmosphere of the partially dissociated ammonia has a reducing effect on the passivity of the oxide layer, which facilitates nitrogen diffusion into the element to be treated.
  • this method is not very successfully applicable to austenitic steels.
  • FR-A-1.453.876 describes a process which includes a thermal aftertreatment of chemically or galvanically coated substrates at a temperature of over 700 ° C. in a protective gas atmosphere, the substrates or layers consisting of the elements of atomic numbers 23- 28, 41-46, 73-78 and 91-96 of the Periodic Table, and which was illustrated, among other things, with the solution relating to the production of upper layers in the corrosion and wear resistant structural steels.
  • the inventive method according to claim 1 eliminates the technological disadvantages shown.
  • the surfaces on which the outermost cover layer is to be formed are galvanically coated with an iron layer.
  • the continued gas nitriding is carried out in the atmosphere without depassivation additives.
  • the coated iron layer forms an oxygen-collecting partition during the thermal-chemical treatment, and it has a homogeneously penetrable structure for nitrogen diffusion.
  • the result is an increased rate of diffusion of nitrogen in the steel, the repeatability of the parameters of the elements produced, and a reduced sensitivity to moisture in the gas atmosphere - which creates favorable conditions for use in series production.
  • the process is non-toxic and enables the outer cover layer to be reached on the entire element or selected areas of the element.
  • the method according to the invention is illustrated in more detail by the description of the exemplary process for producing the nitrided layer on the stem of the exhaust valve of an internal combustion engine.
  • the valve is made of austenitic steel type 50H21G9N4.
  • the degreased valve becomes the electrochemical depassivation subjected to a sodium gluconate bath.
  • the galvanic coating of the valve stem is carried out by the customer to achieve an iron coating with a thickness of 0.002 mm.
  • the next operation after the valve has dried is the chemical-thermal treatment of gas nitriding.
  • the valve is placed in a retort hermetically connected to the ammonia gas system.
  • the oven tempering at a temperature of 575 ° C for 2 hours causes the wear and smear-resistant layer to be produced on the shaft, and the valve disk is coated with an oxide layer, which makes diffusion impossible.
  • the enclosed picture shows the metallographic section of the valve stem in a 500x magnification.
  • the hardness measurements made gave the following values: For diffusion layer 1 1030HV0.02 - Document 3 690HV0.02 -Core 370HV0.02

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)
EP19870108108 1986-06-04 1987-06-04 Verfahren zur Herstellung von äusseren Decksschichten an den hitzebeständigen sowie korrosionsfesten insbesondere austenitischen Stählen Expired - Lifetime EP0248431B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PL259905 1986-06-04
PL25990586A PL147547B1 (en) 1986-06-04 1986-06-04 Method of producing superficial layers on heat-resisting and stainless steels in particular austenitic ones

Publications (3)

Publication Number Publication Date
EP0248431A2 EP0248431A2 (de) 1987-12-09
EP0248431A3 EP0248431A3 (en) 1990-01-31
EP0248431B1 true EP0248431B1 (de) 1993-10-06

Family

ID=20031520

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870108108 Expired - Lifetime EP0248431B1 (de) 1986-06-04 1987-06-04 Verfahren zur Herstellung von äusseren Decksschichten an den hitzebeständigen sowie korrosionsfesten insbesondere austenitischen Stählen

Country Status (5)

Country Link
EP (1) EP0248431B1 (cs)
CS (1) CS274730B2 (cs)
DD (1) DD263308A5 (cs)
DE (1) DE3787672D1 (cs)
PL (1) PL147547B1 (cs)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6086684A (en) * 1997-06-04 2000-07-11 Japan Science And Technology Corporation Electric discharge surface treating method and apparatus
WO2004007789A2 (en) * 2002-07-16 2004-01-22 Danmarks Tekniske Universitet-Dtu Case-hardening of stainless steel
EP1850619A1 (en) 2006-04-28 2007-10-31 Motorola, Inc. Capability update during call

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07119420A (ja) * 1993-10-27 1995-05-09 Fuji Oozx Inc チタン又はチタン合金製エンジンバルブの表面処理方法
US6547888B1 (en) * 2000-01-28 2003-04-15 Swagelok Company Modified low temperature case hardening processes
US7751320B2 (en) * 2006-09-30 2010-07-06 Alcatel-Lucent Usa Inc. Admission control of sessions with preference lists
CN111826654A (zh) * 2020-07-06 2020-10-27 安徽省赛威输送设备有限公司 一种提高提升机壳体耐腐性的处理方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1453876A (fr) * 1965-05-13 1966-07-22 Ct Tech De L Ind Horlogere Procédé de traitement de pièces à revêtements métalliques de grande dureté età forte protection contre la corrosion et pièces à revêtements métalliques obtenues selon ce procédé
JPS5114837A (en) * 1974-07-27 1976-02-05 Tokyo Heat Treating Sutenresukono shintanaruiha nanchitsukashorihoho
US4326898A (en) * 1978-11-13 1982-04-27 Massachusetts Institute Of Technology Method for forming material surfaces

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6086684A (en) * 1997-06-04 2000-07-11 Japan Science And Technology Corporation Electric discharge surface treating method and apparatus
WO2004007789A2 (en) * 2002-07-16 2004-01-22 Danmarks Tekniske Universitet-Dtu Case-hardening of stainless steel
WO2004007789A3 (en) * 2002-07-16 2004-03-18 Univ Danmarks Tekniske Case-hardening of stainless steel
EP1850619A1 (en) 2006-04-28 2007-10-31 Motorola, Inc. Capability update during call

Also Published As

Publication number Publication date
CS274730B2 (en) 1991-10-15
CS411987A2 (en) 1991-02-12
EP0248431A3 (en) 1990-01-31
EP0248431A2 (de) 1987-12-09
DE3787672D1 (de) 1993-11-11
PL147547B1 (en) 1989-06-30
DD263308A5 (de) 1988-12-28

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