Development of Warm Punch Using Friction Heat

Abstract

In press forming, most forming is performed cold. However, warm or hot forming is used for hard materials. In the present study, we focused on the heat generated by friction between metals and worked on the development of the warm punch that utilizes frictional heat. In the experiments, the heater jig and the rotary jig were prepared as different metals for friction. The test materials were steel materials, such as stainless steel and alloy tool steel. After frictional heating, the surface conditions of the different metals were observed by microscope. The wear depth due to friction was also measured. The temperatures generated by the rotation of the different metals differed in the time of heat generation for the combination of the two metals. In the case of stainless steel with low thermal conductivity, the temperature at the punch tip increased to around 400°C. The wear depth increased slowly with increasing time of wear in the rotary and heater jigs. The proposed method allowed the punch to be heated. The possibility of forming processing resistant material by warm deep drawing was found.