Allmanna Svenska Elektriska Aktiebolaget

Asea Ab

Asea

Hans Larker

Jan Nilsson

Jan Adlerborn

Sven-Erik Isaksson

Bertil Lundback

Erik Lundblad

Martin Burstrom

Method and apparatus for plastically de-forming material in a high pressure cylinder, the material being pre-formed into a mandrel billet with an attachment portion and a piston at respective opposite ends thereof and interconnected by an intermediate portion having a smaller cross section than the piston. Holder structure releasably mounted within the high pressure cylinder adjacent the pressure chamber retains the mandrel billet and includes securing means at one end for retaining the attachment portion and engagement means at the other end for slidably engaging the piston. Pressurization of the pressure chamber generates an increase in the pressure medium which acts on the transition surface between the intermediate portion and the piston to cause an elongation of the intermediate portion of the mandrel billet.

Method and apparatus for plastic deformation at high ambient pressure

In the hydrostatic extrusion of tubes in a press which has a pressure chamber containing a high pressure cylinder, a pressure generating portion insertable into the cylinder, a die arranged in the cylinder and a mandrel axially fixed in relation to the die and composed of a carrier portion and a tip, and in which the tip forms with the opening in the die a gap in which a tubular billet is shaped into a tube by hydrostatic extrusion, in connection with the insertion of the tubular billet, a seal is produced initially between the mandrel and the hole in the billet at a point between the front part of the mandrel carrier and the hollow wall of the billet. This may be done by producing a constriction of the front end of the hole in the billet before the mandrel is inserted therein or by upsetting the billet against the die.

Method for hydrostatic extrusion of tubes

For hydrostatically hot pressing bodies of borides, carbides or nitrides of titanium, zirconium or chromium from a powder having an excess of boron, carbon or nitrogen, the power is enclosed in a sealed container of a material which forms compounds with boron, carbon or nitrogen which have a melting point at least equal to that of the material of the container. Container materials may be for example metals from Group IVb of the Periodic System, particularly titanium and zirconium or their alloys in the case of titanium or chromium compounds and zirconium or zirconium base alloys in the case of zirconium compounds. This allows pressing at temperatures of up to 1700.degree.-1800.degree. C, which is high enough to cause bonding between the powder grains.

Method of manufacturing powder bodies of borides, carbides or nitrides

For detecting leakage past a high pressure seal which seals a space in which a high pressure exists, there is arranged outside the high pressure seal a collection space for pressure medium which leaks into the space and a device is provided connected with the space to detect changes in the pressure or temperature therein and to produce a signal or to stop the press. The detecting device may be an insulated cable which seals the space on the side remote from the high pressure seal and which may be broken by pressure within the space, thereby interrupting an electrical circuit.

High pressure apparatus having means for detecting a leakage

In a press for hydrostatic extrusion which has a prestressed outer supporting member and an inner tube or liner, the end surfaces of the inner tube are inwardly inclined towards its center with an inclination of at least 1:20, and the seal holders which take up forces operating on the seals have inclined end surfaces which make contact with the inclined end surface of the inner tube. The sealing arrangement includes a first sealing ring with a cylindrical inner surface which contacts the punch and the die respectively, and an end surface making contact with the support ring, and a second sealing ring with an outer cylindrical sealing surface which makes contact with the inner tube and an inclined end surface which makes contact with the inclined end surface of the support ring.

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Robertsfors, Sweden

Hans Larker