Abstract
An extrusion billet is usually homogenized, cooled, and preheated for extrusion by either gas or induction heating. The metallurgical structure of the billet may be modified by a solution treatment during the preheat cycle. In this paper experiments to determine the effect of a solution treatment step during the preheat cycle are described. Torsion tests were performed to establish the optimum preheat cycle and to determine the effect of the modified sequence on the constitutive relationships of the material. Subsequent extrusion tests confirmed that significant increases in ram speed could be obtained and the permissible working area of extrusion limit diagrams could be enlarged by the modified preheat.
MST/122