Control of Slide Motion in Hot Impression Die Forging of Aluminium Alloy Billets Using Servo Press

Slide motion in hot impression die forging of an aluminium alloy billet was controlled by a servo press to improve the filling of die cavities and the forging load. The filing of a die cavity in hot die forging of a piston was changed by the slide speed. The spike forging test generally used for evaluation of lubricants in cold forging was applied un order to investigate the effect of the slide motion in hot impression die forging. The degree of the filling has a peak for the slide speed, because the distribution of temperature influencing the metal flow was changed by the slide motion. Plastic deformation is caused during the holding of the dies at the bottom dead centre by the elastic recovery of the tools and press induced from the decrease in flow stress, and thus the maximum forging load necessary for a product shape was decreased. In addition, a die quench forging process having the holding at the bottom dead centre was developed to eliminate the solution heat treatment in the conventional T6 process of aluminium alloy products.