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WO1992011106A1 - Procede et dispositif pour la fabrication de pieces frittees a densite elevee - Google Patents

Procede et dispositif pour la fabrication de pieces frittees a densite elevee Download PDF

Info

Publication number
WO1992011106A1
WO1992011106A1 PCT/DE1991/000983 DE9100983W WO9211106A1 WO 1992011106 A1 WO1992011106 A1 WO 1992011106A1 DE 9100983 W DE9100983 W DE 9100983W WO 9211106 A1 WO9211106 A1 WO 9211106A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
pressure chamber
sintered
sintering
sample container
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.)
Ceased
Application number
PCT/DE1991/000983
Other languages
German (de)
English (en)
Inventor
Hans Peter Buchkremer
Detlev STÖVER
Ludger Wenning
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.)
Forschungszentrum Juelich GmbH
Original Assignee
Forschungszentrum Juelich GmbH
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 Forschungszentrum Juelich GmbH filed Critical Forschungszentrum Juelich GmbH
Priority to DE59107394T priority Critical patent/DE59107394D1/de
Priority to EP92901336A priority patent/EP0563140B1/fr
Publication of WO1992011106A1 publication Critical patent/WO1992011106A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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

Definitions

  • the invention relates to a method for producing dense sintered workpieces by sintering powdery material with subsequent hot isostatic pressing (HIP).
  • the sintering is carried out under vacuum.
  • the sintered intermediate product which is subsequently to be compressed by the HIP step is referred to below as the "sintered intermediate product”.
  • Vacuum sintering followed by a HIP step is used to densify workpieces almost to their theoretically possible material density. It has been found that undesired contamination of the sintered intermediate product occurs if, during sintering under vacuum, desorbents dissolve from the walls which enclose the space to be evacuated, which are deposited on the powder particles of the material to be sintered. Passive layers are formed which disturb the sintering processes and prevent a material structure with exclusively closed porosity and impair the product quality. The closed porosity is a prerequisite for an immediately subsequent HIP step with the aim of further densifying the material up to its theoretically possible density.
  • a purging gas which is chemically inert to the powder material is then introduced into the pressure chamber in the vicinity of the green body to be sintered while the green body or bodies are vacuum-sintered while maintaining low pressure. Flushing with inert gas prevents chemical reactions with the material of the green body to be sintered, but essentially prevents oxidation. Intermediates with closed porosity are formed during sintering, which can be hot isostatically compressed directly after the vacuum sintering.
  • the pressure during vacuum sintering is expediently not set above 10 mbar.
  • the pressure is preferably between 1-10 mbar.
  • the invention also relates to a pressure chamber for carrying out the method according to the invention.
  • the pressure chamber has one on a vacuum pump
  • REPLACEMENT LEAF connected vacuum line and a compressed gas line connected to a high pressure pump.
  • the sample container can be heated to the sintering and HIP temperature.
  • a flushing gas line is introduced according to the invention according to claim 4, which opens at the sample container in such a way that a flushing gas flows in at low pressure via the flushing gas line during sintering into the pressure chamber and surrounds the powdery material to be sintered can.
  • the purge gas line opens into a purge gas chamber provided on the sample container. The purge gas flows from this to the green bodies.
  • the invention is explained in more detail below on the basis of an exemplary embodiment.
  • the drawing shows schematically a pressure chamber with a mold container suitable for sintering.
  • a pressure vessel 1 is shown in the drawing, the pressure chamber 2 of which is thermally insulated from the environment. Electrical heating elements 3, 4 are arranged within the pressure chamber 2. The heating elements 3 heat an upper, the heating elements 4 a vertically below heating zone in the pressure chamber. The heating zones are indicated in the drawing with reference numbers 5 and 6.
  • thermocouples 7 to 9 The actual temperature in the heating zones is determined by thermocouples 7 to 9.
  • a controller 10 which controls the switching on and off of the heating elements 3, 4 regulates the temperature in the pressure chamber 2 via the thermocouples 7 to 9 to a predetermined target temperature.
  • the pressure in the pressure chamber 2 is determined outside the pressure vessel.
  • the pressure chamber 2 is connected on the one hand to a vacuum line 11 with a vacuum valve 12, and on the other hand to a pressure gas line 13 with a pressure valve
  • a sliding loading table 15 with a sample holder 16 for receiving green bodies 17 made of powdered material to be sintered.
  • the green bodies 17 have the preform of the sintered body to be produced, they are open-pore.
  • a purge gas line 18 leads to the sample container 16 for purging the sample container with argon.
  • the purging gas flows into a purging gas chamber 19 and is guided out of this to the green bodies 17.
  • the purge gas is withdrawn from the sample container 16 via a suction line 20.
  • the temperature of the purge gas after passage of the powdery material is measured by a thermocouple 21.
  • the purge gas drawn off flows via the suction line 20 to a gas analyzer 22 and is examined there for its impurities.
  • the pressure vessel 1 has thermal insulating plates 23 which protect the pressure chamber 2 against heat losses to the outside.
  • green bodies were produced from U 700 (UDIMET 700).
  • the powdery material for the green bodies had an average powder grain size of ⁇ 45 ⁇ m.
  • Cylindrical green bodies were used to produce ring-shaped sintered pieces.
  • the green bodies were stacked on top of one another in the sample container 16 and sintered for half an hour while introducing argon under vacuum at a pressure of 10 mbar and a temperature of 1270 ° C.
  • the sintered intermediate products were hot isostatically pressed without prior removal from the pressure chamber 2 and without intermediate cooling at a temperature of 1150 ° C. and a pressure of 150 MPa.
  • the HIP process took 3 hours.
  • the manufactured workpiece rings had a theoretical density.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)

Abstract

Pour la fabrication de pièces frittées à densité élevée par frittage de compacts verts, lesquels sont frittés sous vide à partir d'un matériau pulvérulent, puis compactés en produits de frittage intermédiaire par compression isostatique à température élevée (HIP), il est prévu de laver les compacts verts pendant le frittage sous vide avec du gaz inerte en maintenant une basse pression. Il est respecté une pression < 10 mbar dans les limites de 1 à 10 mbar. Pour la réalisation du procédé convient un dispositif où une conduite de gaz de circulation (18) débouche dans un réservoir d'échantillons (16). Pour l'aspiration du gaz de circulation est prévue une conduite d'aspiration (20) évacuant le gaz de circulation de la chambre de pression après passage autour du ou des compact(s) à fritter (17).
PCT/DE1991/000983 1990-12-22 1991-12-17 Procede et dispositif pour la fabrication de pieces frittees a densite elevee Ceased WO1992011106A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE59107394T DE59107394D1 (de) 1990-12-22 1991-12-17 Verfahren und einrichtung zum herstellen hochdichter sinterwerkstücke
EP92901336A EP0563140B1 (fr) 1990-12-22 1991-12-17 Procede et dispositif pour la fabrication de pieces frittees a densite elevee

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4041514.7 1990-12-22
DE4041514A DE4041514C2 (de) 1990-12-22 1990-12-22 Verfahren zum Herstellen dichter Sinterwerkstücke

Publications (1)

Publication Number Publication Date
WO1992011106A1 true WO1992011106A1 (fr) 1992-07-09

Family

ID=6421243

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1991/000983 Ceased WO1992011106A1 (fr) 1990-12-22 1991-12-17 Procede et dispositif pour la fabrication de pieces frittees a densite elevee

Country Status (3)

Country Link
EP (1) EP0563140B1 (fr)
DE (2) DE4041514C2 (fr)
WO (1) WO1992011106A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013167289A1 (fr) * 2012-05-05 2013-11-14 Wdt-Wolz-Dental-Technik Gmbh Insert de frittage pour four de frittage destiné au frittage sans oxygène du métal ou de la céramique
EP2868407A3 (fr) * 2013-11-04 2015-11-25 Thermo-Star GmbH Dispositif de frittage

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1590953A (en) * 1977-10-04 1981-06-10 Powdrex Ltd Making articles from metallic powder
DE3808123A1 (de) * 1988-03-11 1988-07-07 Krupp Gmbh Verfahren zur herstellung von sinterteilen aus feinkoernigen metall- oder keramikpulvern

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS526716A (en) * 1975-06-30 1977-01-19 Gen Electric Silicon carbide sintered articles
SE447610B (sv) * 1985-04-02 1986-11-24 Asea Atom Ab Sett att tillverka sintrade kernbrenslekroppar

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1590953A (en) * 1977-10-04 1981-06-10 Powdrex Ltd Making articles from metallic powder
DE3808123A1 (de) * 1988-03-11 1988-07-07 Krupp Gmbh Verfahren zur herstellung von sinterteilen aus feinkoernigen metall- oder keramikpulvern

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013167289A1 (fr) * 2012-05-05 2013-11-14 Wdt-Wolz-Dental-Technik Gmbh Insert de frittage pour four de frittage destiné au frittage sans oxygène du métal ou de la céramique
EP2868407A3 (fr) * 2013-11-04 2015-11-25 Thermo-Star GmbH Dispositif de frittage

Also Published As

Publication number Publication date
DE59107394D1 (de) 1996-03-21
DE4041514A1 (de) 1992-07-02
EP0563140A1 (fr) 1993-10-06
DE4041514C2 (de) 1995-05-24
EP0563140B1 (fr) 1996-02-07

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