Patent GB-1177223-A (GB)
Title: Improvements in Hydrostatic Extrusion Apparatus
Inventor: GREEN DEREK
IPC: B21C23/00
Filed: 1966-02-04
Abstract: 1,177,223. Extrusion. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 24 Jan., 1967 [4 Feb., 1966; 13 May, 1966 (2); 8 June, 1966 (2)], Nos. 4982/66, 21389/66, 21390/66, 25488/66 and 25489/66. Heading B3P. A hydrostatic extrusion apparatus comprises an extrusion container 1 housing an extrusion die 3 and a plug member 4 with a longitudinal bore 22 through which passes the billet 22, the plug member having means 27 for clamping and sealing the billet in the bore during extrusion. The plug 4 is slidably sealed in the container bore 2 by a copper ring 6 and a rubber ring 7 and has an enlarged head 8 working in a cylinder 9 carried by a press ram 10. A duct 13 connects the container bore with the cylinder 9. For extruding a long billet 22, the ram 10 is moved downwardly thereby pressurizing the hydraulic fluid 27 in the container bore 2 which applies clamping pressure to split jaws (24), Figs. 2, 3 (not shown), of the clamping means 23 and also presses a rubber sealing sleeve (25) against the billet. The pressure of the fluid extrudes the billet through the die and this may be assisted by axial loading of the billet due to hydraulic pressure acting upon the head 8. A lead-in ring 14 is placed against the die. In a modification, Fig. 4 (not shown), the duct 13 is omitted and the container is connected to a constant pressure bleed duct (28). In another modification, Fig. 9 (not shown), a series of billets (271) arranged end to end and supplied along a trough (272) are extruded directly through the die. In another embodiment, Figs. 7, 8 (not shown), the plug member (212) is fixed and the die (204) is mounted on an axially movable plunger (203). The extruded product passes outwardly through a right-angle passageway (210) in the plunger. In a modification, Figs. 10, 11 (not shown), a tube (317) is produced by indirect hydrostatic extrusion of a long tubular billet (331) between a fixed mandrel (332) and an axially movable die (304). Instead of a long billet, separate tubular billets may be used and are pressure-welded together during extrusion, or they may be initially joined together end to end by seamwelding. Alternatively, the billets may be split longitudinally, fitted over the mandrel and the longitudinal seam then welded. Another modification is described, Fig. 12 (not shown), for indirectly extruding a cable sheath (317) around a cable core (338) or for forming a nuclear fuel element by sheathing a core of uranium or uranium dioxide with stainless steel, magnesium or zirconium alloy. In another modification, Fig. 13 (not shown), a billet used for cable sheathing is formed by helically wrapping a strip (339) around a mandrel (332) and welding the helical seam 340 by an argon arc-welding torch; alternatively a strip may be folded about a mandrel to form a longitudinal seam which is then welded. In another embodiment, Fig. 5 (not shown), both the plug member (116) and the die (132) move axially towards each other during extrusion. The hydraulic fluid is pressurized from an external source (149). In this embodiment the amount of axial loading may be varied and hydraulic fluid may also act upon the extruded product through port (133) after removal of a blanking ring (134). In another embodiment, Fig. 14, the extrusion container 401 has two axially movable plug members 406, 419 arranged in tandem to act alternately upon a long billet 444 which is thus extruded continuously through die 403. Each plug member has split clamping jaws (416), Fig. 16 (not shown), and a rubber sealing sleeve (417). High-pressure liquid for effecting the extrusion is supplied by a pump 434 and reservoir 433. Low-pressure liquid is supplied by pump 442 for retracting the rear member 419. In this embodimentthe extrusion may be performed with or without axial loading.