Pugh, H. Ll. D.
Head of Plasticity Division, National Engineering Laboratory, Glasgow,
Pages: 73 Published: Jan 1965
The paper is concerned with the mechanical properties and the extrusion of materials under pressure up to about 200,000 psi. Apparatus is described for carrying out tension and torsion tests under pressure. Results are given and discussed on the effect of pressure on: the ductility of various materials, the correlation of the fracture stress obtained in tension and torsion tests under pressure, and on the variation with pressure of the ratio of the radii of the minimum cross section to that of the curvature at the neck. Typical stress-strain curves under pressure are given, as are some results on the effect of soaking at pressure on the atmospheric tensile properties.
Two applications of high pressure to the extrusion of metals are described: one, hydrostatic extrusion, in which a high-pressure liquid instead of a ram is used to extrude metals; the other, in which the metal is extruded into or against a hydrostatic pressure thus allowing the satisfactory extrusion of brittle metals. Results are given of the hydrostatic extrusion of a number of materials, and the mechanics of the process are discussed. The potential of the method for the extrusion of long billets is illustrated.
Paper ID: STP45128S