EP0912458B1 - Sinterverfahren - Google Patents

Sinterverfahren Download PDF

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Publication number
EP0912458B1
EP0912458B1 EP97932066A EP97932066A EP0912458B1 EP 0912458 B1 EP0912458 B1 EP 0912458B1 EP 97932066 A EP97932066 A EP 97932066A EP 97932066 A EP97932066 A EP 97932066A EP 0912458 B1 EP0912458 B1 EP 0912458B1
Authority
EP
European Patent Office
Prior art keywords
bar
cemented carbide
bodies
weight
sintering
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
EP97932066A
Other languages
English (en)
French (fr)
Other versions
EP0912458A1 (de
Inventor
Barbro Rohlin
Margareta Palsson
Leif Akesson
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.)
Sandvik AB
Original Assignee
Sandvik AB
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
Priority claimed from SE9602751A external-priority patent/SE9602751D0/xx
Priority claimed from SE9602752A external-priority patent/SE9602752D0/xx
Application filed by Sandvik AB filed Critical Sandvik AB
Publication of EP0912458A1 publication Critical patent/EP0912458A1/de
Application granted granted Critical
Publication of EP0912458B1 publication Critical patent/EP0912458B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
    • C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
    • C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
    • C22C29/08—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1003—Use of special medium during sintering, e.g. sintering aid
    • B22F3/1007—Atmosphere
    • B22F3/101—Changing atmosphere
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1017—Multiple heating or additional steps
    • B22F3/1028—Controlled cooling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/05—Mixtures of metal powder with non-metallic powder
    • C22C1/051—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
    • 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
    • C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
    • C23C30/005—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process on hard metal substrates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2201/00—Treatment under specific atmosphere
    • B22F2201/01—Reducing atmosphere
    • B22F2201/013—Hydrogen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2201/00—Treatment under specific atmosphere
    • B22F2201/10—Inert gases
    • B22F2201/11—Argon

Definitions

  • the present invention relates to a sintering method for cemented carbide for the purpose of eliminating the binder phase layer from its surface before applying coatings on said surface.
  • Coated cemented carbide inserts have now for many years been commercially available for chip forming machining of metals in the metal cutting industry.
  • Such inserts are commonly made of a metal carbide, normally WC, generally with addition of carbides of other metals such as Nb, Ti, Ta, etc. and a metallic binder phase of cobalt.
  • a wear resistant material such as TiC, TiN, Al 2 O 3 etc. separately or in combination it has been possible to increase the wear resistance at essentially maintained toughness.
  • binder phase layer generally ⁇ 1 ⁇ m thick on their surface. This particularly applies to inserts with a binder phase enrichment in the surface below the coating, so called cobalt gradient but also to inserts with even distribution of binder phase. In the latter case this layer forms on certain grades but not on other. The reason to this is not understood at present. However, the layer has a negative effect on the process when carrying out CVD- or PVD-deposition, which results in layers with inferior properties and insufficient adherence. The binder phase layer must therefore be removed before carrying out the deposition process.
  • Figure 1 shows in 4000x magnification a top view of the surface of cemented carbide inserts partly covered with a binder phase layer.
  • Figure 2 shows in 4000x magnification a top view of the surface of a cemented carbide insert sintered according to the invention.
  • the dark grey areas are the Co-layer
  • the light grey angular grains are WC
  • the grey rounded grains are the so called gamma phase which is (Ti,Ta,Nb,W)C.
  • the heating and high temperature steps of the sintering is performed in the conventional way.
  • cooling from sintering temperature down to at least ⁇ 1200°C is performed in a hydrogen and argon atmosphere of 0.4 to 0.9 bar, preferably 0.5 to 0.8 bar pressure of hydrogen and rest argon.
  • the total pressure shall be >0.5 to 100 bar, preferably >0.5 to 10 bar, most preferably >0.5 to 1 bar, the argon pressure always being >0.1 bar.
  • the best conditions depend on the composition of the cemented carbide, on the sintering conditions and to a certain extent on the design of the equipment used.
  • the sintering should lead to a Co content on the surface of nominal content +6/-4%, preferably +4/-2%.
  • the Co content can be determined e.g. by the use of a SEM (Scanning Electron Microscope) equipped with an EDS (Energy Dispersive Spectrometer) and comparing the intensities of Co from the unknown surface and a reference, e.g. a polished section of a sample of the same nominal composition.
  • the method of the invention can be applied to all kinds of cemented carbides preferably to cemented carbide with a composition of 4 to 15 weight-% Co, up to 20 weight-% of the cubic carbides TiC, TaC, NbC and rest WC. Most preferably the cemented carbide has a composition 5 to 12 weight-% Co, less than 12 weight-% of the cubic carbides TiC, TaC, NbC and rest WC.
  • the average WC grain size shall be ⁇ 8 ⁇ m, preferably 0.5-5 ⁇ m.
  • Inserts according to the invention are after sintering provided with a thin wear resistant coating including at least one layer by CVD-, MTCVD- or PVD-technique as known in the art.
  • Cemented carbide inserts of type CNMG 120408 with 5.5 weight-% Co, 8.5 weight-% cubic carbides and 86 weight-% WC of 2 ⁇ m average WC-grain size were sintered in a conventional way at 1450°C and cooled to room temperature in argon. The surface was up to 50% covered with a Co-layer, Fig 1.
  • Inserts of the same composition and type were sintered in the same way but cooled from 1400 to 1200°C temperature in 0.5 bar hydrogen and rest argon and from 1200°C in pure argon atmosphere.
  • the surface was to about 6% covered with Co, which corresponds to the nominal Co content, Fig 2.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Powder Metallurgy (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)
  • Chemical Vapour Deposition (AREA)

Claims (5)

  1. Verfahren zum Sintern von Hartmetallkörpern unter Erhitzen der Körper auf die Sintertemperatur in einer geeigneten Atmosphäre und Kühlen, dadurch gekennzeichnet, daß das Kühlen wenigstens bis ≤ 1200°C in einer Wasserstoffatmosphäre mit einem Druck von 0,4 bis 0,9 bar und Rest Edelgas, vorzugsweise Argon, mit einem Druck von >0,1 bar mit einem Gesamtdruck von >0,5 bis 100 bar, vorzugsweise >0,5 bis 10 bar, durchgeführt wird.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Wasserstoff 0,5 bis 0,8 bar ist.
  3. Verfahren nach einem der vorausgehenden Ansprüche, dadurch gekennzeichnet, daß das Hartmetall die Zusammensetzung 4 bis 15 Gew.-% Co, bis zu 20 Gew.-% der kubischen Karbide TiC, TaC, NbC und Rest WC hat.
  4. Verfahren nach einem der vorausgehenden Ansprüche, dadurch gekennzeichnet, daß das Hartmetall die Zusammensetzung 5 bis 12 Gew.-% Co, weniger als 12 Gew.-% der kubischen Karbide TiC, TaC, NbC und Rest WC hat.
  5. Verfahren nach einem der vorausgehenden Ansprüche, dadurch gekennzeichnet, daß die Körper mit einer dünnen verschleißbeständigen Beschichtung einschließlich wenigstens einer Schicht durch CVD-, MTCVS- oder PVD-Technik versehen sind.
EP97932066A 1996-07-11 1997-06-23 Sinterverfahren Expired - Lifetime EP0912458B1 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
SE9602751 1996-07-11
SE9602751A SE9602751D0 (sv) 1996-07-11 1996-07-11 Sintering method
SE9602752 1996-07-11
SE9602752A SE9602752D0 (sv) 1996-07-11 1996-07-11 Sintering method
PCT/SE1997/001111 WO1998002394A1 (en) 1996-07-11 1997-06-23 Sintering method

Publications (2)

Publication Number Publication Date
EP0912458A1 EP0912458A1 (de) 1999-05-06
EP0912458B1 true EP0912458B1 (de) 2002-03-06

Family

ID=26662713

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97932066A Expired - Lifetime EP0912458B1 (de) 1996-07-11 1997-06-23 Sinterverfahren

Country Status (5)

Country Link
EP (1) EP0912458B1 (de)
JP (1) JP2000515110A (de)
AT (1) ATE214044T1 (de)
DE (1) DE69710899T2 (de)
WO (1) WO1998002394A1 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE509566C2 (sv) * 1996-07-11 1999-02-08 Sandvik Ab Sintringsmetod
ATE351930T1 (de) 2000-03-24 2007-02-15 Kennametal Inc Werkzeug aus zementiertem karbid und verfahren seiner herstellung
US6638474B2 (en) 2000-03-24 2003-10-28 Kennametal Inc. method of making cemented carbide tool

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60110838A (ja) * 1983-11-16 1985-06-17 Sumitomo Electric Ind Ltd 超硬合金及びその製造法
JPH02190403A (ja) * 1989-01-19 1990-07-26 Mitsubishi Metal Corp 表面被覆炭化タングステン基超硬合金製切削工具の製造法
US5453241A (en) * 1991-02-05 1995-09-26 Sandvik Ab Cemented carbide body with extra tough behavior

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3837006C3 (de) * 1988-10-31 1993-11-18 Krupp Widia Gmbh Hartmetall

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60110838A (ja) * 1983-11-16 1985-06-17 Sumitomo Electric Ind Ltd 超硬合金及びその製造法
JPH02190403A (ja) * 1989-01-19 1990-07-26 Mitsubishi Metal Corp 表面被覆炭化タングステン基超硬合金製切削工具の製造法
US5453241A (en) * 1991-02-05 1995-09-26 Sandvik Ab Cemented carbide body with extra tough behavior

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 199036, Derwent World Patents Index; Class L02, AN 1990-271173 *

Also Published As

Publication number Publication date
EP0912458A1 (de) 1999-05-06
WO1998002394A1 (en) 1998-01-22
DE69710899T2 (de) 2002-11-28
DE69710899D1 (de) 2002-04-11
JP2000515110A (ja) 2000-11-14
ATE214044T1 (de) 2002-03-15

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