Paper 14: Augmented Hydrostatic Extrusion of Continuous Bar

Abstract

The development of simple hydrostatic extrusion has shown that one of its more useful features is the complete lack of friction between the billet and its containing vessel. The only limitation on the length; diameter ratio of extrusion billets has thus been the size of the containing vessel, whether it be a long vessel for long straight billets or a large-diameter vessel for coiled billets. This limitation has been one of the disadvantages of hydrostatically extruding extremely long bar. An extrusion device is described which surmounts this problem in that the workpiece is cyclically fed through a ratchet action clamp into the pressurized system from outside the device. The workpiece is in the form of straight bar and therefore may be of large diameter, of indefinite length and, if necessary, in brittle material. The principle involved is that of augmented hydrostatic extrusion already employed on the Atomic Energy Authority 1600 tons hydrostatic extrusion machine. One of the most satisfactory features of the system is the absence of the high energy release at the completion of simple hydrostatic extrusion.