Abstract
The axial tensile residual stress is generated on surface of bar after drawing. This residual stress causes bending and decrease of fatigue strength by machining or by heat treatment process. Therefore reduction of residual stress is very important for industrial use. In this study, Angle-type die and Circle-type die were used to research the optimum geometry of die. The effect of bearing length on residual stress was also studied. As results, the optimum geometry of die is : (1)entrance of die had better-to use angle-type, (2)corner radius is enlarged comparatively in the exit and (3)bearing length is enlarged.
