GB1215452A - Improvements in or relating to hydrostatic extrusion apparatus - Google Patents

Abstract

1,215,452. Hydrostatic extrusion. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 24 Jan., 1968 [2 Feb., 1967], No. 5149/67. Heading B3P. A hydrostatic extrusion apparatus has means for bleeding high-pressure liquid from the eextrusion chamber 1, comprising a leak path 23 formed between two contacting members 20, 22 which are loaded to provide a controllable pressure between the contacting surfaces. Member 20 is the extrusion plunger actuated by a main ram 5 and passing through a bleed ring 22 which has a conical surface 24 and is compressed axially by hydraulic pressure in a secondary cylinder 3. This causes radial contraction of the ring 22 on to the plunger 20. Ram 5 is carried by an axially movable crosshead 10 containing a cylinder 8 for a main actuating ram 13. For extruding a billet 29 through die 16, ram 13 is moved to the left to pressurize liquid 30 in cylinders 8, 3 and move the ram 5. Movement of the crosshead 10 and ram 5 is initially restrained by cylinder 14 until the plunger has built up hydrostatic pressure in chamber 1. The crosshead 10 is then released whereby plunger 20 moves into engagement with the billet which is thus extruded by combined hydrostatic and direct pressure. During extrusion liquid is bled along path 23 into cylinder 3. In another embodiment, Fig. 2 (not shown), the extrusion chamber 1 is formed by segments (31) and has a liner (32) whose rear end (34) is contracted on to the plunger 20 to provide the bleed path. In a further embodiment, Fig. 3 (not shown), the bleed ring (42) surrounds the extrusion die 16. In another embodiment, Fig. 4a, the extrusion plunger 127 has an enlarged rear head 128 with an annular surface 131 contacting the end of the main ram 104. The bleed path is provided by duct 134, contacting surface 131, outer chamber 133, and passageway 135 leading to atmosphere. The extrusion chamber is formed by segments 113, Fig. 5 (not shown), having an inner liner 118 and an outer sleeve 116 which is pressurized during extrusion of the billet 137 by the liquid 138 in chamber 102 which is itself pressurized by forward movement of the ram 104. In a modification, Fig. 6 (not shown), a continuous billet (147) is used and passes through the ram 104. (For Figures see next page.)