Review Lecture: Hydrostatic extrusion

Abstract

The object of this lecture is to present an account of a technological development which has taken place within the last twenty years, from very simple beginnings founded largely on the pioneer high-pressure work of the late P. W. Bridgman, to a metal-forming process of considerable industrial interest. Extrusion, defined as the operation of producing rods, tubes and various complex sections by forcing a billet of metal through a suitable die with a ram, is a comparative newcomer among the industrial methods whereby metals are wrought into useful forms. It was first used to manufacture lead pipes, in the early eighteenth century, and for lead sheathing of electric cables about seventy years ago. The inventive genius of Alexander Dick, whose first patent was taken out in 1894, led to the use of hot extrusion for copper and its alloys and to the design of large machines with high throughput. Extrusion of steel has attained significance only within the past fifteen years.