51 巻 (2010) 597 号 p. 958-962
Slide motion in hot die forging of an aluminum alloy billet was controlled by a servo press to improve the filling of die cavities and forging load. The filling of a die cavity in the hot die forging of a piston was changed by changing slide speed. The spike forging test generally used for evaluation of lubricants in cold forging was applied to the evaluation of slide motion in hot die forging. The degree of filling has a peak of the slide speed, because the distribution of temperature affecting the metal flow was changed by slide motion. The deformation of the billet continued when the dies ware held at the bottom dead center owing to the elastic recovery of the dies and press induced by the decrease in flow stress. 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 center was developed to eliminate solution heat treatment in the conventional T6 process for aluminum alloy products.