EP0039013A1 - Procédé d'extrusion - Google Patents

Procédé d'extrusion Download PDF

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Publication number
EP0039013A1
EP0039013A1 EP81102952A EP81102952A EP0039013A1 EP 0039013 A1 EP0039013 A1 EP 0039013A1 EP 81102952 A EP81102952 A EP 81102952A EP 81102952 A EP81102952 A EP 81102952A EP 0039013 A1 EP0039013 A1 EP 0039013A1
Authority
EP
European Patent Office
Prior art keywords
capsule
powder
die
pressing
deformable material
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.)
Withdrawn
Application number
EP81102952A
Other languages
German (de)
English (en)
Inventor
Hans Gunnar Ing. Larsson
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
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 ASEA AB filed Critical ASEA AB
Publication of EP0039013A1 publication Critical patent/EP0039013A1/fr
Withdrawn legal-status Critical Current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
    • B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding

Definitions

  • the invention relates to an extrusion process according to the preamble of claim 1.
  • "Elongated bodies" in the sense of claim 1 are massive strands, especially those whose shape and dimensions are suitable for further processing by rolling. Pipe compacts also fall under the term mentioned.
  • the pressed product can have a very high density. The perfect theoretical density can be achieved directly by pressing or by subsequent hot working.
  • Extruding powder encapsulated in capsules has been hindered by many problems. Among other things, with the previous methods, great problems arise from folding the capsule sheet. In an article entitled “The Consolidation of Metal Powder by Hot Working within Sheaths" in "Powder Metallurgy" 1958, No. 1, 2, pages 94 to 103, I. Williams describes various methods for producing products from powder. Extrusion is described in a section. Folding the capsule sheet is said to be a serious limitation of this method. In order to reduce the risk of folding, it has been proposed to press the capsule isostatically in the cold state before the extrusion in order to obtain a density of at least 80% of the theoretically possible density. Such compression is possible with material that gives a soft powder when granulated. In contrast, this method is not suitable for material that forms a hard, spherical powder. A capsule with high-speed steel powder cannot be pressed together in such a way that a sufficient density is achieved.
  • the invention has for its object to develop an extrusion process of the type mentioned, in which the above-mentioned difficulties are substantially eliminated.
  • the invention makes it possible to extrude a powder-filled capsule in the cold state without pre-pressing with a good result, the density of the powder in the capsule need not be greater than can be achieved by vibration when filling the capsule.
  • the procedure after The invention enables hard, spherical powder to be extruded which cannot be compacted by cold isostatic pressing.
  • the density of an aspherical powder that can be achieved by vibration is normally between 67 and 72% of the theoretical density.
  • a capsule filled with metal powder is heated to a temperature required for the binding of the metal powder grains to one another at a corresponding pressing pressure, whereupon the capsule is inserted into a press and an insulating layer made of an easily deformable powder which is thermally stable at the pressing temperature a layer structure of powder grains that glide easily against one another, such as talc or pyrophyllite, is surrounded.
  • a piston is pushed into the press chamber and exerts such pressure on the capsule and the surrounding material that the capsule with its contents and the surrounding material are pressed out through the opening of a die at one end of the press chamber.
  • the talc or the other material that surrounds the capsule essentially prevents the capsule sheet from folding when pressed.
  • the heat-insulating property of the material means that the capsule material is not cooled to a greater extent by heat conduction to the press chamber wall. Thanks to this property, the capsule does not need to be heated to overtemperature in consideration of heat losses. This limitation of heating in turn reduces the risk of undesired grain growth.
  • the method according to the invention has the further advantage that no residue of the compact remains in the pressure chamber or die. By placing a sufficient amount of talc between the compact and the pressure-generating piston, a complete squeezing out of the compact can be achieved. It is therefore not necessary to replace the die after every pressing process.
  • the density that can be achieved depends not only on the temperature but also on the degree of reduction during extrusion.
  • the density increases with the degree of reduction and can change with a large Re degree of production approximate the theoretical density.
  • With vigorous rolling after pressing, the desired final final density is then achieved. It is also possible to achieve a perfect density with a small degree of reduction.
  • the powder-filled capsule is first exposed to a very high pressure in the press chamber when the die opening is closed in a first pressing process. The die opening is then exposed, and the powder-filled capsule is pressed out through the die at a considerably lower pressure. Precompacting the compact can be accomplished in many different ways by delaying the start of extrusion.
  • a sheet metal plate can be placed between the die and the die support.
  • Its strength can be chosen to tear when the desired pre-compaction pressure has been reached, after which the extrusion begins. It is also possible to design the capsule with an end plate of such a thickness that it forms such a resistance at the start of the extrusion that the desired precompacting pressure is reached. A slidable plug can also be used, which is removed after the pre-compaction has been carried out.
  • the cross-sectional reduction should be greater than 2: 1, preferably greater than 6: 1. In cases where the powder-filled capsule is pressed in two stages, it must be subjected to an axial pressure during the first pressing stage, which takes place with the die opening closed, which pressure exceeds 1 kbar, preferably -4 kbar.
  • Talc is a suitable auxiliary material for pressing, which is both heat-insulating and can be deformed in a suitable manner. It is also important that talc is readily available and cheap. Filling the space between the capsule and the baling chamber wall can be facilitated by appropriate grain size distribution of the talc used.
  • the pressing properties can be improved by the talc with a lubricant such as.
  • Another way to facilitate pressing is to coat the inside surface of the pressure chamber with an anti-friction agent such as polytetrafluoroethylene.
  • the gap between the capsule and the surrounding press chamber wall must have a certain minimum size.
  • the talc layer must have a certain thickness with regard to thermal insulation and pressing. A layer thickness of 10 to 40 mm is considered appropriate.
  • the compact consists of a hollow capsule shaped like a cylinder, which is filled with powder.
  • the central inner channel of the tubular compact is filled with talc or a similar easily deformable material of the same type as the material surrounding the compact.
  • a pre-pressed rod made of talc is expediently inserted into the pipe compact.
  • a solid mandrel with a layer of talc between the mandrel and the inner tube wall can also be used. This structure is advantageous when pressing products with small holes. It is also possible to press products with several parallel channels by providing the compact with several parallel holes.
  • the compact can be constructed from several different materials.
  • a tubular compact can be made of simple steel in its outer region and stainless material in its inner region. In certain cases it may be advisable to leave the talc or other material in the pipe or in the channels during the subsequent processing after pressing.
  • the press frame 1 consists of the yokes 2 and 3, the stand 4 and a force-absorbing band jacket 5.
  • a die support 6 with a channel 9 is fastened to the lower yoke 2 with the aid of a mounting ring 7.
  • An actuating cylinder 8 with an actuating piston 10 is fastened in the upper yoke 3.
  • a pressure generating piston 11 is connected to the actuating piston 10 by means of a disc 12 which is provided with guide rollers 13 which run on rails on the stand 4.
  • Adjustment cylinders, not shown, are provided for lifting the pressure generating piston 11 and for pushing the actuating piston 10 into the cylinder 8.
  • In the press frame there is a press cylinder 14 with end flanges 15 and 16 which are provided with guide rollers 17 which run on rails on the stand 4.
  • the press cylinder can be moved vertically with the aid of the adjusting cylinders 18, which are fastened in the upper part of the press frame 1 and whose piston rods 20 are connected to the lower flange 15 of the press cylinder.
  • the capsule 23 is surrounded by an easily deformable material 24, which is preferably talcum powder.
  • the disc 21 serves as an explosive plate and is in such Used cases in which the capsule 23 is to be pre-compacted before extrusion. When a certain pressing force has been reached, the disk 21 tears and the extrusion begins.
  • the capsule material and the surrounding insulating, easily deformable material (talc) 24 exit together through the die 22, as shown in FIG.
  • talc easily deformable material
  • FIG. 3 When a tubular compact with a core 25 made of deformable material is pressed, a product with a core is obtained, as shown in FIG. Talc, which surrounds the metal product and which forms the core when pressing pipes, is brittle after pressing and can be removed without difficulty.
  • the tubular compact consists of the outer and inner metal capsule walls 23a and 23b, which together form a hollow cylindrical capsule, and the powder 26 filled into this capsule. In FIG. 3, despite its similar representation, this powder 26 must not be light deformable material 24 and 25 can be confused.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)
  • Lubricants (AREA)
  • Extrusion Of Metal (AREA)
EP81102952A 1980-04-25 1981-04-16 Procédé d'extrusion Withdrawn EP0039013A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8003139 1980-04-25
SE8003139A SE426791B (sv) 1980-04-25 1980-04-25 Forfarande vid strengpressning av en pulverfylld kapsel

Publications (1)

Publication Number Publication Date
EP0039013A1 true EP0039013A1 (fr) 1981-11-04

Family

ID=20340832

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81102952A Withdrawn EP0039013A1 (fr) 1980-04-25 1981-04-16 Procédé d'extrusion

Country Status (4)

Country Link
US (1) US4388054A (fr)
EP (1) EP0039013A1 (fr)
JP (1) JPS56163021A (fr)
SE (1) SE426791B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2533468A1 (fr) * 1982-09-23 1984-03-30 Nyby Uddeholm Ab Capsule pour ebauches servant a l'extrusion de pieces, notamment de tubes
US5308232A (en) * 1988-12-20 1994-05-03 Institut Strukturnoi Makrokinetiki Akademii Nauk Sssr Apparatus for making products from powdered materials

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2542228B1 (fr) * 1983-03-10 1985-08-02 Cegedur Procede de frittage sous pression de poudres d'alliages d'aluminium
US4632702A (en) * 1985-10-15 1986-12-30 Worl-Tech Limited Manufacture and consolidation of alloy metal powder billets
US5480601A (en) * 1986-06-17 1996-01-02 Sumitomo Electric Industries, Ltd. Method for producing an elongated sintered article
US4699657A (en) * 1986-11-03 1987-10-13 Worl-Tech Limited Manufacture of fine grain metal powder billets and composites
EP0327064A3 (fr) * 1988-02-05 1989-12-20 Anval Nyby Powder Ab Procédé de fabrication d'objets par la métallurgie des poudres, en particulier d'objets allongés tels que barres, profils, tubes, etc.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1129039B (de) * 1957-01-14 1962-05-03 Heinz Schmalz Dr Ing Verfahren zum Herstellen stranggepresster Halbzeuge hoher Festigkeit
US3344507A (en) * 1962-12-19 1967-10-03 Atomic Energy Authority Uk Hydrostatic extrusion of sheathed ceramic nuclear fuel material
FR1576752A (fr) * 1967-07-31 1969-08-01
US3922763A (en) * 1974-12-26 1975-12-02 Douglas Jay Buerger Fabric fastener

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3645728A (en) * 1970-06-03 1972-02-29 Gen Motors Corp Method for making spark plug shells
US3723109A (en) * 1971-07-16 1973-03-27 Int Nickel Co Extrusion of canned metal powders using graphite follower block
GB1369843A (en) * 1971-09-10 1974-10-09 Pyrotenax Ltd Manufacture of composite welding electrodes
JPS5146500B2 (fr) * 1973-02-06 1976-12-09
US3892030A (en) * 1974-04-29 1975-07-01 Us Air Force Method of fabricating a billet from metal preforms and metal powder

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1129039B (de) * 1957-01-14 1962-05-03 Heinz Schmalz Dr Ing Verfahren zum Herstellen stranggepresster Halbzeuge hoher Festigkeit
US3344507A (en) * 1962-12-19 1967-10-03 Atomic Energy Authority Uk Hydrostatic extrusion of sheathed ceramic nuclear fuel material
FR1576752A (fr) * 1967-07-31 1969-08-01
US3922763A (en) * 1974-12-26 1975-12-02 Douglas Jay Buerger Fabric fastener

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2533468A1 (fr) * 1982-09-23 1984-03-30 Nyby Uddeholm Ab Capsule pour ebauches servant a l'extrusion de pieces, notamment de tubes
US5308232A (en) * 1988-12-20 1994-05-03 Institut Strukturnoi Makrokinetiki Akademii Nauk Sssr Apparatus for making products from powdered materials

Also Published As

Publication number Publication date
SE8003139L (sv) 1981-10-26
US4388054A (en) 1983-06-14
SE426791B (sv) 1983-02-14
JPS56163021A (en) 1981-12-15

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19820406

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18W Application withdrawn

Withdrawal date: 19831020

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Inventor name: LARSSON, HANS GUNNAR, ING.