Extrusion of Powders I

Abstract

The demands of an advancing technology are providing an opportunity for metal powder producers and organizations which are competent in extrusion to jointly supply products to meet its requirements. The technical and perhaps economic attributes of using particulate material will best be achieved when methods of fabrication are available to consolidate the materials into useful shapes at normal metal-working costs. Extrusion is perhaps ideally suited to meet this need in many cases, particularly when the length to diameter ratio is high as in rods, tubes, and special shapes. In extrusion, we find a process suited to prototype, small volume production in the 100-lb class as well as tonnage output. Extrusion is also an economically attractive process, insofar as it offers simultaneous densification and reduction in area of from 6 to over 100 times in a single operation. No other process can yield deformation of this magnitude and under conditions so ideally suited to powders, i.e., high compressive forces. These high unit pressures (up to 250,000 psi), which are characteristic of extrusion, enable powders to be densified and deformed at temperatures which are lower than those required for sintering or even hot pressing.