EP0246162B1 - Verfahren zum Sintern von Pulvermaterial in einem Durchlaufofen - Google Patents

Verfahren zum Sintern von Pulvermaterial in einem Durchlaufofen Download PDF

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Publication number
EP0246162B1
EP0246162B1 EP87401098A EP87401098A EP0246162B1 EP 0246162 B1 EP0246162 B1 EP 0246162B1 EP 87401098 A EP87401098 A EP 87401098A EP 87401098 A EP87401098 A EP 87401098A EP 0246162 B1 EP0246162 B1 EP 0246162B1
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EP
European Patent Office
Prior art keywords
furnace
sintering
hydrogen
atmosphere
powder
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
EP87401098A
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English (en)
French (fr)
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EP0246162A1 (de
Inventor
Michel Madsac
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.)
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Publication date
Application filed by LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority to AT87401098T priority Critical patent/ATE50936T1/de
Publication of EP0246162A1 publication Critical patent/EP0246162A1/de
Application granted granted Critical
Publication of EP0246162B1 publication Critical patent/EP0246162B1/de
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Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • 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
    • B22F3/001—Starting from powder comprising reducible metal compounds
    • 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
    • B22F3/11—Making porous workpieces or articles
    • B22F3/1143—Making porous workpieces or articles involving an oxidation, reduction or reaction step
    • 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
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the present invention relates to a sintering process in a continuous furnace of a powder material containing oxygen in the form of oxide and / or in adsorbed form, in which the oxygen present is reduced during a first step pre-sintering, and then ensures the cohesion of the material during a second sintering step.
  • Sintering operations are generally carried out in continuous ovens under a controlled atmosphere. More and more nitrogen-based atmospheres are used in these sintering furnaces to replace the atmospheres generated by exothermic generators or by ammonia crackers, on the one hand because the flow control of synthetic atmospheres is more easy and on the other hand, because their composition can be modified according to the characteristics of the process. Furthermore, the exothermic generators have a very variable dew point and it is necessary to have a large quantity of hydrogen in the atmosphere of the furnace, in order to maintain the reducing nature of this atmosphere and avoid the oxidation of the powder. or the support on which it is sintered.
  • a commonly used protective atmosphere contains inert gases such as nitrogen and reactive gases capable of reducing oxides, such as hydrogen and / or carbon monoxide.
  • the purpose of the pre-sintering step in particular in the absence of a binder between the various grains of powder, is intended to reduce the oxides present in the powder and generally, to reduce the oxygen present in the layer of powder. It is therefore necessary that the atmosphere contains the reducing qualities required.
  • the purpose of the sintering step is in particular to increase the intergranular cohesion as well as the diffusion at the interface of the grains and of the support when the sintering is carried out on a separate support.
  • This sintering step also requires an atmosphere of a reducing nature, avoiding the entry of air into the hot zone and the oxidation of the powder which would slow down the sintering of the latter.
  • the pre-sintering step was the step of the process on which the productivity of a production line depended, for a determined quality of sintering.
  • the parameter P (H 2 ) f is the lowest value measured at a point in the oven corresponding to the total reduction of the oxides, the flow of atmosphere being sufficient to ensure the complete reduction of the oxides as well as a corresponding sintering and adhesion. to a predetermined value.
  • S p represents the mean section of the parts in the plane perpendicular to the oven mat.
  • a layer of 0.9 mm of powder is deposited containing 73% copper, 23% lead and 4% tin.
  • the width of the support on which the powder is deposited is 200 mm, the density of the powder is 5.2 T / m 3 and the percentage of oxygen in the powder is 0.28%.
  • the ribbon advances at the speed Vs in the furnace, consisting of a pre-sintering furnace 30 meters in length at a temperature of 820 ° C, at the outlet of which the ribbon and the powder are laminated between two steel cylinders , then introduced into the sintering oven (30 meters in length - 820 ° C), each pre-sintering and sintering oven has a cooling zone 10 meters in length ("water-jacket" type).
  • the atmosphere is injected into the pre-sintering and sintering furnaces near the junction of the hot and cooling zones.
  • the method according to the invention makes it possible to accelerate the speed (at constant speed) or to reduce the flow (at constant speed) in the pre-sintering furnace, but also makes it possible to reduce the gas flow in the sintering furnace with an atmosphere containing less hydrogen, which overall results in a significant reduction in production costs.
  • Such tapes can be used as self-lubricating pads.
  • a 0.7 mm layer of nickel powder is deposited on a sheet of pre-nickel-plated carbon steel used as a support.
  • the width of the support on which the powder is deposited is 150 mm, the density of the powder is 0.8 T / M 3 and the percentage of oxygen in the powder is 0.18%.
  • the ribbon advances at speed Vs in the oven, consisting of a hot zone at the temperature of 1040 ° C., 4 m in length, followed by a cold zone of the "water-jacket" type.
  • the atmosphere is injected into the oven at the junction between the hot zone and the cold zone as well as at the end of the cold zone. It consists of 10% hydrogen and 90% nitrogen.
  • the coefficient a is determined as indicated above: the measured value is 20%.
  • the flow rate of 6 m 3 / h of atmosphere containing 10% of H 2 by volume is maintained by 90% of N 2 by volume.
  • a material is obtained having the predetermined sintering qualities identical to those obtained by using an ammonia cracker-burner generating an atmosphere containing 10% hydrogen, and 90% nitrogen at a flow rate of 6 m3 / hour, but with a material advance speed of around 80 m / h.
  • Such tapes can be used as porous electrodes for alkaline batteries.

Landscapes

  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Powder Metallurgy (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Ceramic Products (AREA)
  • Ceramic Capacitors (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
  • Tunnel Furnaces (AREA)
  • Coloring Foods And Improving Nutritive Qualities (AREA)
  • Crushing And Pulverization Processes (AREA)
  • Seasonings (AREA)

Claims (5)

1. Sinterverfahren in einem Druchlaufofen für ein pulverförmiges Material, welches Sauerstoff in Form von Oxid und/oder in adsorbierter Form enthält, wodurch der anwesende Sauerstoff im Verlauf einer ersten Vorsinterstufe reduziert und dann die Kohäsion des Materials im Verlauf einer zweiten Sinterstufe sichergestellt wird, dadurch gekennzeichnet, daß die Vorsinterstufe in einer reduzierenden Atmosphäre auf der Grundlage von Wasserstoff und neutralem Gas vonstatten geht, wobei die Ausbeute FG mindestens der Gleichung entspricht:
Figure imgb0006
worin:
FG in m3/h ausgedrückt wird
Sp = Querschnitt der zu sinternden Pulverschicht in m2,
Dp = volumenbezogene Masse des Pulvers in kg/m3,
X(O2)i = Massenprozentsatz Sauerstoff in Pulver vor der Vorsinterstufe in Form von Oxid und/oder in adsorbierter Form,
P/H2)i = Volumprozentsatz Wasserstoff in dem in den Ofen eingeleiteten Gas,
P(H2)f = geringster Volumprozentsatz Wasserstoff in der Ofenatmosphäre an einem Punkt, wo die Oxide ... reduziert sind.
Vs Vorschubgeschwindigkeit des Materials im Ofen, ausgedrückt in m/h a ist eine Konstante gleich (He)V(He)i+(He)o die durch Einleitung einer Stickstoff- und Wasserstoffatmosphäre in den Sinterofen auf übliche Weise bestimmt wird, in dem dem eingeleiteten Gas ein bestimmtes Volumen Spürgas, wie z.B. Helium, während einer bestimmten Zeitdauer zugesetzt wird und gleichzeitig am Eintritt und am Austritt des Ofens die Entwicklung des Heliumanteils im aus dem Ofen austretenden Gas als Funktion der Zeit registriert wird und wobei die Integration dieses Heliumanteils als Funktion der Zeit am Eintritt und am Austritt des Ofens, (He); bzw. (He)o, bewirkt wird.
2. Sinterverfahren nach Anspruch 1, dadurch gekennzeichnet, daß das pulverförmige Material aus einem oder mehreren Metalloxiden besteht.
3. Sinterverfahren nach Anspruch 1, dadurch gekennzeichnet, daß das pulverförmige Material aus einem oder mehreren Metallen besteht.
4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß das pulverförmige Material auf einer Metallauflage gesintert wird.
5. Verfahren nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß die im Sinterofen erzeugte Atmosphäre eine Atmosphäre ist, die auch Wasserstoff und ein neutrales Gas enthält, dessen Wasserstoffkonzentration geringer ist als die der Vorsinteratmosphäre.
EP87401098A 1986-05-16 1987-05-15 Verfahren zum Sintern von Pulvermaterial in einem Durchlaufofen Expired - Lifetime EP0246162B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87401098T ATE50936T1 (de) 1986-05-16 1987-05-15 Verfahren zum sintern von pulvermaterial in einem durchlaufofen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8607067 1986-05-16
FR8607067A FR2598641B1 (fr) 1986-05-16 1986-05-16 Procede de frittage dans un four continu de materiau en poudre

Publications (2)

Publication Number Publication Date
EP0246162A1 EP0246162A1 (de) 1987-11-19
EP0246162B1 true EP0246162B1 (de) 1990-03-14

Family

ID=9335326

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87401098A Expired - Lifetime EP0246162B1 (de) 1986-05-16 1987-05-15 Verfahren zum Sintern von Pulvermaterial in einem Durchlaufofen

Country Status (12)

Country Link
US (1) US4713215A (de)
EP (1) EP0246162B1 (de)
JP (1) JPS62274003A (de)
AT (1) ATE50936T1 (de)
AU (1) AU587757B2 (de)
BR (1) BR8702497A (de)
DE (1) DE3761881D1 (de)
ES (1) ES2013767B3 (de)
FR (1) FR2598641B1 (de)
GR (1) GR3000295T3 (de)
PT (1) PT84873B (de)
ZA (1) ZA873505B (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH681516A5 (de) * 1989-09-13 1993-04-15 Asea Brown Boveri
JP3167313B2 (ja) * 1990-07-24 2001-05-21 シチズン時計株式会社 部品の製造方法
US6856051B2 (en) * 2001-10-03 2005-02-15 Delphi Technologies, Inc. Manufacturing method and composite powder metal rotor assembly for circumferential type interior permanent magnet machine
US6655004B2 (en) 2001-10-03 2003-12-02 Delphi Technologies, Inc. Method of making a powder metal rotor for a surface
US6675460B2 (en) 2001-10-03 2004-01-13 Delphi Technologies, Inc. Method of making a powder metal rotor for a synchronous reluctance machine

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888663A (en) * 1972-10-27 1975-06-10 Federal Mogul Corp Metal powder sintering process
US3979234A (en) * 1975-09-18 1976-09-07 The United States Of America As Represented By The United States Energy Research And Development Administration Process for fabricating articles of tungsten-nickel-iron alloy
US4137106A (en) * 1976-07-26 1979-01-30 Sumitomo Electric Industries, Ltd. Super hard metal roll assembly and production thereof
US4190440A (en) * 1977-06-24 1980-02-26 American Can Company Process for fabricating steel from ferrous metal particles
JPS5420909A (en) * 1977-07-17 1979-02-16 Sumitomo Electric Ind Ltd Method of apparatus for sintering supper hard alloy
US4139375A (en) * 1978-02-06 1979-02-13 Union Carbide Corporation Process for sintering powder metal parts
CA1190418A (en) * 1980-04-21 1985-07-16 Nobuhito Kuroishi Process for producing sintered ferrous alloys
US4436696A (en) * 1981-05-20 1984-03-13 Air Products And Chemicals, Inc. Process for providing a uniform carbon distribution in ferrous compacts at high temperatures
JPS5839707A (ja) * 1981-09-01 1983-03-08 Kobe Steel Ltd 粉末成形体の高密度焼結法

Also Published As

Publication number Publication date
AU587757B2 (en) 1989-08-24
FR2598641B1 (fr) 1988-08-26
BR8702497A (pt) 1988-02-23
ATE50936T1 (de) 1990-03-15
GR3000295T3 (en) 1991-03-15
JPS62274003A (ja) 1987-11-28
EP0246162A1 (de) 1987-11-19
DE3761881D1 (de) 1990-04-19
ZA873505B (en) 1987-11-09
ES2013767B3 (es) 1990-06-01
US4713215A (en) 1987-12-15
FR2598641A1 (fr) 1987-11-20
PT84873A (fr) 1987-06-01
PT84873B (pt) 1990-02-08
AU7293787A (en) 1987-11-19

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