ABSTRACT
Rapid progress of science and technology has led to a demand for new materials, different combinations of materials, and production quantities of special alloys in super-pure conditions. This chapter describes several methods of high pressure metal-working, including the different forms of hydrostatic extrusion. Hydrostatic extrusion is essentially a method of extruding a billet through a die by means of pressurized fluid. Hydrostatic extrusion is particularly suitable for the extrusion of composite billets. The large stresses which are imposed upon the extrusion tooling during the generation and containment of the very high pressures used in hydrostatic extrusion require that considerable attention be paid to the design of the items. With reasonably good lubrication the contribution of friction to the total extrusion pressure for hydrostatic extrusion is small, particularly for large ratios. Hydrostatic extrusion is particularly suitable for the extrusion of composite billets. The use of a superimposed hydrostatic pressure can inhibit cracking when brittle materials are worked.
