Abstract:
A press for hot hydrostatic extrusion of a billet, has a stand, a pressure chamber axially movable in the stand to engage a die mounted in one end against a die support carried by the stand, a punch slidable in the pressure chamber to raise a pressure medium in the pressure chamber to extrusion pressure, and a billet holder slidable in the chamber for pressing the billet against the die during sliding movement of the pressure chamber to closing position. In order to prevent contact between the die support and the die until extrusion is about to begin, with consequent cooling of the billet which interferes with the extrusion, an annular canted spring is arranged in a groove in the face of the die support opposite the die so as to prevent contact therebetween during closing movement of the pressure chamber.
Abstract:
In the hydrostatic extrusion of compound billets, in which the billet is formed of a core of one material and a casing surrounding the core of another material, and in which a gap is left during the assembly of the billet to allow for deformation of the casing, the core is provided with a point and the casing has an inwardly directed conical flange within which the point of the core rests. At the back end, the core is provided with a sealing device for preventing the entry of fluid into the space between the core and the casing. In order to prevent the compression of the air in the space between the core and the casing, the core is provided at its front end with passages which open into the point of the core and which communicate with the space between the core and the casing, providing an air escape arrangement.
Abstract:
For hydrostatic extrusion, a press is provided having a yoke. One of the end pieces of the yoke carries a die receiving block having an extrusion passage therethrough. A pressure cylinder is mounted within the yoke for movement towards and from the die receiving block. Slidable in the cylinder of the high pressure cylinder is a billet holder which divides the space within the cylinder into two parts. The billet holder has a spring controlled valve which prevents passage of pressure fluid therethrough until a predetermined pressure differential exists between the chambers. A punch is provided for sliding into and out of the high pressure cylinder on the opposite side thereof from the die. The die and billet are first positioned between the high pressure cylinder and the die receiving block, after which the high pressure cylinder is moved to enclose the billet. Then pressure is applied in the high pressure cylinder on the side of the punch to move the billet holder against the billet and move the billet into engagement with the die. Then the pressure behind the the billet holder is increased so that the fluid passes through the billet holder and thereafter further increased by advancing the punch into the high pressure cylinder so that the fluid exerts sufficient pressure on the billet to extrude it. Before opening the high pressure cylinder, the punch is withdrawn and cool pressure fluid is admitted into the end of the cylinder remote from the punch.
Abstract:
In a high pressure press which has a seal holder, a high pressure seal is provided between the wall of a high pressure cylinder and a die or an axially movable plunger projecting into the cylinder, which is composed of two sealing rings, one of which has an outer surface abutting the cylindrical wall and an end surface abutting the seal holder, while the other ring has a cylindrical surface abutting the plunger and a surface abutting the seal holder. The portion of the outer surface of the first ring abutting the cylindrical wall which is nearest to the seal holder is provided with generally longitudinally extending draining channels therein.
Abstract:
A die for manufacturing rods of rectangular cross-section from a core of aluminium or an aluminium alloy and a casing of copper or a copper alloy by hydrostatic extrusion of a compound billet of such materials has a cup-shaped bottom which may be spherical, ellipsoidal, hyperbolic or parabolic in cross-section and a conical upper part. The bottom parts of the generatrices in axial section through the die form an angle which is between 120* and 180*, preferably between 150* and 170*, and a conical upper part has a cone angle between 40* and 120*.
Abstract:
In a high pressure pressure press which has a seal holder, a high pressure seal is provided between the wall of a high pressure cylinder and a die or an axially movable plunger projecting into the cylinder, which is composed of two sealing rings, one of which has an outer surface abutting the cylindrical wall and an end surface abutting the seal holder, while the other ring has a cylindrical surface abutting the plunger and a surface abutting the seal holder. The portion of the outer surface of the first ring abutting the cylindrical wall which is nearest to the seal holder is provided with generally longitudinally extending draining channels therein. The sealing ring which makes contact with the inner cylindrical wall of the chamber is prestressed and has a normal outer diameter which is more than 0.1 per cent greater than that of the high pressure cylinder, thus making contact with the cylindrical wall with a force dependent on the prestressing.
Abstract:
For hydrostatic extrusion, a press is provided having a yoke. One of the end pieces of the yoke carries a die receiving block having an extrusion passage therethrough. A pressure cylinder is mounted within the yoke for movement towards and from the die receiving block. Slidable in the cylinder of the high pressure cylinder is a billet holder which divides the space within the cylinder into two parts. The billet holder has a spring controlled valve which prevents passage of pressure fluid therethrough until a predetermined pressure differential exists between the chambers. A punch is provided for sliding into and out of the high pressure cylinder on the opposite side thereof from the die. The die and billet are first positioned between the high pressure cylinder and the die receiving block, after which the high pressure cylinder is moved to enclose the billet. Then pressure is applied in the high pressure cylinder on the side of the punch to move the billet holder against the billet and move the billet into engagement with the die. Then the pressure behind the billet holder is increased so that the fluid passes through the billet holder and thereafter further increased by advancing the punch into the high pressure cylinder so that the fluid exerts sufficient pressure on the billet to extrude it. Before opening the high pressure cylinder, the punch is withdrawn and cool pressure fluid is admitted into the end of the cylinder remote from the punch.