Conduction heating of boron alloyed steel in application for hot stamping

Abstract

In traditional hot stamping process, heating of the sheet by radiation heating occupies most of cycle time, which limits the application of hot stamping in automotive industry. Thus a faster heating method has great significance on the hot stamping. The conduction heating overcomes shortage of the radiation heating because of higher heating rate and greater energy efficiency. It attracts increasing attention in the application of heating blanks in hot stamping. In the present study, a movable conduction heating device on die was designed in terms of the Joule’s Law. Heating experiments of boron alloyed steel were performed using the developed device. Heating rate and uniform temperature region were investigated in the non-heat preservation condition (NHPC) and the heat preservation condition (HPC). The results revealed that in the HPC, the heating rate was improved by 13.1 °C/s. In addition, the length of the uniform temperature region was lengthened by 15 mm. It was demonstrated that the HPC was preferred. Furthermore, it was indicated that the mechanical properties of the blanks in uniform temperature region of the conduction heating were also superior to that of the radiation heating.