GB1025593A - Improvements in and relating to the shaping of metal by pressure - Google Patents

Abstract

1,025,593. Extruding; forging. BALDWIN-LIMA-HAMILTON CORPORATION. July 29, 1963 [July 27, 1962], No. 30044/63. Headings B3H and B3P. In the flow deformation of a metal billet, particularly by extrusion, there is provided in the confining surfaces a peripheral zone of low pressure 198 to which a fluid is admitted to treat the flowing metal. The billet 192 is extruded between a mandrel 211 and die orifice 197 to form a tube 206. The mandrel may act to pierce a solid billet and may be integral with or separate from the ram. Low pressure zones such as 198 and 204 are provided in the die entry surface and the container wall 191 and supplied with fluid through duct 205. A low pressure zone 212 is also provided on the mandrel 211 and supplied with fluid through ducts 215, 216. The fluid may be a lubricant, coolant or an insulating medium; examples given are powdered or flaked graphite, castor oil, powdered glass, chlorides of borax or barium or sodium; fluorides of barium or cadmium or cerium or chromium, and gases containing vaporized lubricants. One type of fluid may be used as a lubricant and after extrusion a different fluid is used to clean the working surfaces. The fluid is fed by a pump 104, Fig. 7 (not shown), which may be controlled by a timer. A valve may be incorporated in the ducts leading to the low pressure zones. The press ram 219 has a dummy block 195 and is actuated by a hydraulic cylinder 8, Fig. 1 (not shown). Run-out guides 12, 14, Fig. 1 (not. shown) are provided for the extruded product which may be tubular or solid. Various examples of dies and container bores with low pressure zones are described. In another embodiment, Fig. 11 (not shown), applied to backward extrusion, a hollow ram carries the die which has a low pressure annular zone in its entry surface. Reference is made to the hot extrusion of steel, impact extrusion, forging, punching, and explosive forming.