EP0014975B1 - Procédé de fabrication d'ébauches à partir de poudre métallique - Google Patents

Procédé de fabrication d'ébauches à partir de poudre métallique Download PDF

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Publication number
EP0014975B1
EP0014975B1 EP80100788A EP80100788A EP0014975B1 EP 0014975 B1 EP0014975 B1 EP 0014975B1 EP 80100788 A EP80100788 A EP 80100788A EP 80100788 A EP80100788 A EP 80100788A EP 0014975 B1 EP0014975 B1 EP 0014975B1
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EP
European Patent Office
Prior art keywords
capsule
powder
pressure
press
process according
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
Application number
EP80100788A
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German (de)
English (en)
Other versions
EP0014975A1 (fr
Inventor
Hans-Gunnar Larsson
Erik Westman
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.)
ABB Norden Holding AB
Original Assignee
ASEA AB
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Filing date
Publication date
Application filed by ASEA AB filed Critical ASEA AB
Priority to AT80100788T priority Critical patent/ATE2489T1/de
Publication of EP0014975A1 publication Critical patent/EP0014975A1/fr
Application granted granted Critical
Publication of EP0014975B1 publication Critical patent/EP0014975B1/fr
Expired legal-status Critical Current

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    • 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
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B22F3/15—Hot isostatic pressing

Definitions

  • the invention relates to a process for the production of compacts from powder according to the preamble of claim 1.
  • the compacts are further processed into the desired shapes and dimensions by shaping, such as rolling or forging.
  • the residual porosity is eliminated, so that a material is obtained with a density that is practically equal to the theoretically possible density.
  • Such a method is known from FR-A 2049 146.
  • Compacts or finished parts can be made directly by a number of different pressing processes.
  • the powder is obtained by atomizing a liquid jet of metal.
  • the resulting metal droplets are quickly cooled, giving them a favorable, fine structure.
  • This powder is enclosed in capsules and processed under high pressure using various forging or pressing methods to give a solid body at a temperature which is so far below the melting temperature that undesired structural changes due to grain growth are avoided as far as possible.
  • High-quality tool steel and superalloys are commercially produced on a large scale by hot isostatic pressing of powder-filled capsules, which are compressed in a pressure furnace and at the same time sintered into a practically completely solid body. In this way, both rolled or forged compacts as well as tools that have almost their final shape are produced.
  • the method known from FR-A 2049 146 is used for pressing relatively small compacts, preferably those which already have essentially the shape of the final workpiece.
  • the powder intended for a compact is first pressed into a solid body in various possible ways, which can then be handled and, without a capsule, is embedded in direct contact in a container which cannot be sealed in a gas-tight manner, in a material which has heat-insulating and pressure-transmitting properties.
  • the compact is conveyed to a mechanical press, in which the powder body with the material surrounding it is pressed. In order to prevent the entry of undesired gases, the entire process takes place in a room filled with protective gas.
  • the invention has for its object to further develop a method of the type mentioned in such a way that even large compacts can be produced economically with it.
  • a capsule is first filled with powder and sealed.
  • This capsule is heated to a temperature which allows binding, but which is so far below the melting temperature that the structural change due to grain growth remains insignificant during handling and pressing.
  • the heated capsule is inserted into the mold space of a press and with surrounded by a layer of talc or pyrophyllite.
  • This material is well heat-insulating and easily deformable, so that it transmits the applied compressive forces in such a way that the compact is exposed to all-round pressure even over great lengths.
  • Talc and pyrophyllite are easily deformable and can be distributed relatively easily when pressed so that they exert radial pressure on the capsule. An almost isostatic pressure system is achieved.
  • Talc is an extremely advantageous material because it is easily accessible and inexpensive and has the necessary property to act isostatically on the capsule during pressing and to exert a radial pressure in such a way that the capsule sheet is prevented from folding. Talc also has the required heat insulating properties. This is so good that the temperature in the capsule can be compensated by waiting for the pressing until the surface layer of the material in the capsule, which is cooled during insertion, is transported by heat from the inner parts of the capsule has been reheated.
  • the thickness of the insulating and pressure-transmitting material layer is chosen so that the outside temperature of the material close to the capsule wall can be kept at a value which exceeds the required binding temperature when the capsule is exposed to the compacting pressure.
  • the capsule is advantageously pressed between two punches in an axially movable cylinder which is freely movable during the pressing, so that friction on the cylinder wall impedes the pressing together as little as possible.
  • the insulating and force-transmitting material can be applied around the capsule in various ways. Plates and tubular bushings can be made which are placed around the capsule when the heated capsule is inserted into the press. It is also possible to place the capsule on a plate or on a layer of powder or granules made of the insulating and pressure-transmitting material, to fill the space between the capsule and the surrounding cylinder with a powder or granules and finally to fill the capsule with a plate or to cover a layer of powder or granules.
  • a granulate of talc with such a particle size distribution that the granulate is easy-flowing and at the same time lies with a high degree of filling (density) in the gap between the capsule and the press cylinder.
  • the properties of the talc can be increased by adding a friction-reducing material, such as. As boron nitride, graphite or molybdenum sulfide can be improved.
  • Another way to reduce the friction is to spray a layer of a material with lubricating properties on the inside of the press cylinder.
  • the wall temperature is so low that an organic lubricant can be used - such as.
  • Plates and bushings made of talc can be produced by casting.
  • Talc powder can be mixed with binder and hardener.
  • binder a mixture of 1 part by volume can five percent hydrochloric acid HCl, 10 volumes of ethyl silicate and 15 parts by volume of 90 - proof alcohol can be used. 1 volume of five percent ammonia solution to 20 volumes of binder can be used as hardener.
  • the tubes are cast in a centrifugal casting machine.
  • the method according to the invention makes it possible to press capsules with a large length-diameter ratio.
  • the capsule sheets do not fold.
  • a capsule can be pressed in a single-acting press, the length-diameter ratio of which is five or more.
  • a length is preferably chosen which is two to five times the diameter.
  • the length-diameter ratio of the capsule can be twice the above-mentioned values.
  • the capsule size can vary within wide limits. However, a small capsule volume means a large surface area in relation to the volume, which can result in rapid cooling. This can make pressing difficult before the temperature drops below the temperature required to achieve a good bond. As a result, there is a risk that the required density will not be achieved.
  • the possibility of being able to press a compact with a large length-diameter ratio means that a relatively heavy compact can be pressed in a press with a relatively low pressing force.
  • a press with a pressing force of approx. 30 MN a capsule with a diameter of 330 mm can be pressed at a pressing pressure of approx. 250 MPa. With a length of 1 100 mm, the weight of the capsule is approx. 500 kg.
  • a density that exceeds 99% of the theoretical can be achieved at a temperature of 1 150 ° C, a pressure of 250 MPa and a pressing time of a few minutes. A cycle time of 5 minutes can be achieved. If a compact is thermoformed after pressing, for example by forging or rolling, it is not necessary to achieve a perfect density during pressing. The perfect density can then be achieved by the following processing.
  • the method according to the invention represents a realistic alternative to hot isostatic pressing in a pressurized furnace by means of pressurized gas in cases where a final compacting to a completely homogeneous Material can for example be done in a subsequent rolling process.
  • the investment costs are relatively low, the cycle time is short down to about 5 minutes, so that a large capacity is achieved at a low cost.
  • the process therefore makes powder pressing economical for the production of rolled compacts from a simpler material than is used in the known pressing processes.
  • a major advantage of the method according to the invention is also that the requirements placed on the capsule material and its weld seams are significantly lower than in hot isostatic pressing in a gas atmosphere.
  • the capsule only needs to be filled and shaken (vibrated), the density of the spherical powder filled reaching 65 to 70% of the theoretical density.
  • the capsule is then closed with or without previous evacuation. If an evacuation is carried out, it can then be reconnected to nitrogen gas before it is sealed.
  • the figures show capsules 1 and an oven 2 in which the capsules are heated to a temperature suitable for pressing.
  • a handling robot 3 places a capsule taken from the conveyor belt 4 in the oven 2, takes a heated capsule out of the oven 2 and passes it on to the press 5.
  • the press 5 which is described in more detail with reference to FIGS. 2 and 3, is a hydraulic press. with a press frame 6, in which a vertically movable press cylinder 7 is attached, which is guided by means of rollers 8 and rails 9.
  • the press cylinder 7 can be moved with the aid of hydraulic lifting cylinders 10 between a charging position according to FIG. 2 and a pressing position according to FIG. 3.
  • In the lower part of the press frame 6 there is an actuating cylinder 11 with a piston 12.
  • a stamp 13 adapted to the press cylinder 7 is connected to the piston 12 by means of a holding plate 14 which is fastened to the piston 12 by means of bolts (not shown). This plate is provided with guide rollers 15 which run on the rails 9.
  • the stamp has a length such that its upper end face lies somewhat below the upper end face of the cylinder 7 in the charging position according to FIG. 2.
  • a fixed punch 16 which is fastened in the press frame by means of a ring 17 and bolts, not shown.
  • annular hopper 18 for talc or pyrophyllite 19 is attached in a granular state.
  • This material has heat-insulating and pressure-transmitting properties and is fed to the funnel from a storage container 20 (FIG. 1).
  • Talc is easily accessible and inexpensive, and it is suitable to fill the gap 22 between the capsule 1 and the press cylinder 7 with an appropriate grain size distribution. With regard to the thermal insulation and the filling of the gap 22, this should be at least 25 mm in size.
  • the press cylinder 7 should have a 50 mm larger diameter than the capsule 1.
  • the pressing is carried out as follows: A plate or layer 21 of talc is applied in the cylinder 7 on the stamp 13. With the help of the robot 3, a heated capsule 1 is removed from the oven 2 and placed on the plate 21. The cylinder 7 is raised so that the upper punch 16 protrudes somewhat into the cylinder. During this lifting, material 19 is fed from the hopper 18 to the gap 22, so that an insulating and pressure-transmitting layer 25 is formed. In addition, a material layer 21 is applied to the upper end of the capsule 7. The outer parts of the capsule, in particular the edges, cool down when the capsule is transferred from the oven 2 to the press 5. It may therefore be appropriate to wait a little before pressing until the temperature in the capsule 1 has equalized.
  • the cylinder chamber 23 is supplied with pressure medium from a pressure medium source, not shown, via a line 24, so that the capsule 1 is pressed axially between the punches 13 and 16.
  • the cylinder 7 can freely follow the compact, so that the smallest possible pressing force due to friction and. Slippage between the compact and the cylinder wall is lost.
  • the cylinder assumes the position shown in FIG. 3.
  • the punch 13 and the cylinder 7 are then lowered, and a finished rolled compact is removed using the robot 3.
  • the capsule material must be removed. In many cases, the capsule material in the form of scale disappears during the subsequent rolling and the heating required for this.

Claims (8)

1. Procédé de fabrication d'ébauches à partir de poudre, ces ébauches étant mises à la forme souhaitée par un traitement ultérieur, par exemple par forgeage ou par laminage, procédé dans lequel on transforme d'abord la poudre destinée à l'ébauche en un corps en poudre pouvant être manipulé, qui est chauffé et qui est soumis à la température d'agglomération dans la chambre de mise en forme d'une presse sous une pression telle que les grains de poudre s'agglomèrent et forment un corps solide essentiellement plein, puis on entoure le corps en poudre dans la chambre de mise en forme d'une couche isolante en un matériàu qui, lors de l'introduction ultérieure d'un piston de pression dans la chambre de mise en forme, sert d'agent de transmission de la pression et applique de tout côté une pression sur le corps en poudre, caractérisé en ce que le corps en poudre, qui peut être manipulé, est constitué d'une capsule emplie de poudre et la couche isolante (25) est en talc ou en pyrophyllite.
2. Procédé selon la revendication 1, caractérisé en ce qu'il consiste à charger axialement les deux extrémités de l'ébauche (1) par des poinçons (13, 16) d'un cylindre (7) essentiellement libre de se déplacer axialement pendant la compression.
3. Procédé selon la revendication 1 ou 2, caractérisé en ce qu'il consiste à fixer des plaques (21) en le matériau isolant sur les faces frontales inférieure et supérieure de la capsule (1) et à fixer une douille en matériau isolant autour de la capsule dans le cylindre.
4. Procédé selon la revendication 1 ou 2, caractérisé en ce qu'il consiste à mettre la cap- suie sur une couche (21) en matériau isolant, à emplir l'intervalle annulaire (22) entre la capsule et le cylindre de poudre ou de matériau isolant en grains et à recouvrir la face frontale supérieure de la capsule d'une couche en matériau isolant.
5. Procédé selon la revendication 4, caractérisé en ce qu'il consiste à emplir l'intervalle annulaire (22) entre la capsule et le cylindre de talc sous forme d'un produit granulé, qui a de bonnes propriétés d'écoulement et une répartition granulométrique telle qu'il emplit l'intervalle annulaire avec un degré de remplissage élevé.
6. Procédé selon l'une des revendications précédentes, caractérisé en ce que la couche isolante (25) exerce sur la capsule (1) une pression radiale d'une valeur telle que tout pliage de la tôle de la capsule est empêché.
7. Procédé selon l'une des revendications précédentes, caractérisé en ce qu'il consiste à retarder la compression après avoir effectué l'introduction de la capsule dans la presse de manière à réchauffer d'abord la couche superficielle, qui a été refroidie lors de l'introduction, du contenu de la capsule par compensation de température à partir de l'intérieur de la capsule.
8. Procédé selon l'une des revendications précédentes, caractérisé en ce qu'il consiste à choisir les paramètres de la compression de manière à obtenir à la compression une densité de 100 pour cent et à obtenir la résistance mécanique souhaitée de l'ébauche par le traitement ultérieur.
EP80100788A 1979-02-27 1980-02-16 Procédé de fabrication d'ébauches à partir de poudre métallique Expired EP0014975B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80100788T ATE2489T1 (de) 1979-02-27 1980-02-16 Verfahren zur herstellung von presslingen aus metallpulver.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE7901734A SE417580B (sv) 1979-02-27 1979-02-27 Forfarande for framstellning av emnen fran pulver genom hogt allsidigt tryck
SE7901734 1979-02-27

Publications (2)

Publication Number Publication Date
EP0014975A1 EP0014975A1 (fr) 1980-09-03
EP0014975B1 true EP0014975B1 (fr) 1983-02-16

Family

ID=20337404

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80100788A Expired EP0014975B1 (fr) 1979-02-27 1980-02-16 Procédé de fabrication d'ébauches à partir de poudre métallique

Country Status (6)

Country Link
US (1) US4371396A (fr)
EP (1) EP0014975B1 (fr)
JP (1) JPS55120499A (fr)
AT (1) ATE2489T1 (fr)
DE (1) DE3061951D1 (fr)
SE (1) SE417580B (fr)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE426790B (sv) * 1980-04-25 1983-02-14 Asea Ab Forfarande for isostatisk pressning av pulver i en kapsel
SE430904C (sv) * 1980-05-13 1986-04-06 Asea Ab Rostfritt, ferrit-austenitiskt stal framstellt av pulver
US4596694A (en) * 1982-09-20 1986-06-24 Kelsey-Hayes Company Method for hot consolidating materials
CA1222152A (fr) * 1982-09-20 1987-05-26 Walter J. Rozmus Methode et dispositif thermiques d'agglomeration de materiaux
US4499049A (en) * 1983-02-23 1985-02-12 Metal Alloys, Inc. Method of consolidating a metallic or ceramic body
DE3343210C1 (de) * 1983-11-30 1985-01-10 Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt e.V., 5000 Köln Verfahren und Vorrichtung zur Herstellung verdichteter Formkoerper
JPS6199605A (ja) * 1984-10-18 1986-05-17 Hitachi Zosen Corp 熱間静水圧圧縮焼成法
DE3530741C1 (de) * 1985-08-28 1993-01-14 Avesta Nyby Powder AB, Torshälla Verfahren zur Herstellung pulvermetallurgischer Gegenstaende
CA1284007C (fr) * 1986-02-13 1991-05-14 Robert V. Kromrey Methode et dispositif de moulage par recours a un polymere solide coulant
US5770136A (en) * 1995-08-07 1998-06-23 Huang; Xiaodi Method for consolidating powdered materials to near net shape and full density
US6042780A (en) * 1998-12-15 2000-03-28 Huang; Xiaodi Method for manufacturing high performance components
RU2166409C1 (ru) * 2000-11-08 2001-05-10 Губенко Лев Анатольевич Силовой модуль автоклава
GB0413392D0 (en) * 2004-06-16 2004-07-21 Rolls Royce Plc A method of consolidating a power
US20210086409A1 (en) * 2019-09-19 2021-03-25 Flow International Corporation Systems and methods of interim and end of process treatment of manufactured articles using high pressure and waterjets

Family Cites Families (11)

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Publication number Priority date Publication date Assignee Title
US3284195A (en) * 1963-06-26 1966-11-08 John M Googin Method of fabricating articles from powders
US3356496A (en) * 1966-02-25 1967-12-05 Robert W Hailey Method of producing high density metallic products
US3455682A (en) * 1967-07-31 1969-07-15 Du Pont Isostatic hot pressing of refractory bodies
US3689259A (en) * 1969-06-02 1972-09-05 Wheeling Pittsburgh Steel Corp Method of consolidating metallic bodies
US4041123A (en) * 1971-04-20 1977-08-09 Westinghouse Electric Corporation Method of compacting shaped powdered objects
US3767371A (en) * 1971-07-01 1973-10-23 Gen Electric Cubic boron nitride/sintered carbide abrasive bodies
US3728111A (en) * 1971-09-21 1973-04-17 Asea Ab Method of manufacturing billets from powder
US3982911A (en) * 1972-11-01 1976-09-28 General Electric Company Process for the preparation of a composite cubic boron nitride layer abrasive body
CA1062866A (fr) * 1975-08-22 1979-09-25 Raymond L. Straw Methode pour comprimer un article dans un moule et materiau de support utilise a cette fin
US4205379A (en) * 1977-05-16 1980-05-27 TRW Inc., Systems & Energy Position determining and dynamic positioning method and system for floating marine well drill platforms and the like
US4234661A (en) * 1979-03-12 1980-11-18 General Electric Company Polycrystalline diamond body/silicon nitride substrate composite

Also Published As

Publication number Publication date
DE3061951D1 (en) 1983-03-24
JPS55120499A (en) 1980-09-16
SE7901734L (sv) 1980-08-28
JPS646241B2 (fr) 1989-02-02
ATE2489T1 (de) 1983-03-15
SE417580B (sv) 1981-03-30
EP0014975A1 (fr) 1980-09-03
US4371396A (en) 1983-02-01

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