Characterization of tribological conditions within direct hot stamping

The aim of this study is to create a detailed process understanding regarding the tribological conditions within direct hot stamping. Hot stamping has established as a common technology for manufacturing safety-relevant components in modern car bodies. However, due to the high forming temperatures within hot stamping applications, no suitable lubricants have been developed yet. As a consequence, high friction and severe wear occur during the forming. This affects the tool wear as well as the resulting part quality. For improving the robustness and the efficiency of industrial hot stamping processes, future measures to reduce the tribological loads have to be found. The key to the development of such measures is a detailed process understanding of the tribological conditions. Within this study, friction and wear are analyzed for different workpiece and tool temperatures, relative velocities and contact pressures. Based on the experimental results, detailed knowledge of the critical cause-effect relations between process parameters and tribological behavior is acquired. The friction behavior is analyzed via strip drawing experiments under hot stamping conditions. The amount of wear is determined via confocal microscopy measurements before and after the experiments. The results of this study help to improve the process understanding of the tribological conditions within the hot stamping process and to develop future measures for reducing tool wear.