P 1228 – Tool-side Impact on the Tribological Conditions within Hot Stamping
The lifetime of hot stamping tools, which is mainly affected by adhesive and abrasive wear, is critical regarding the efficiency of industrial hot stamping applications. The tribological conditions in the contact zone between workpiece and tool are therefore a critical factor, which decisively influences the quality of hot stamped components. Considering existing research studies, it becomes clear that existing knowledge about the tribological conditions is not sufficient for reaching a relevant improvement of process design or for developing effective tool-side measures to significantly increase the tool lifetime.
The objective of this research project is to investigate functional relations between the topography of the tool surface, the tool material and the resulting tribological behavior within hot stamping. By understanding the cause-effect-relations, measures for increasing the tool lifetime and thus the efficiency of the hot stamping process will be achieved.
In order to reach the research objective three tool materials have been chosen for the experimental investigations in consultation with industrial partners. Furthermore, various processes for the machining of the tool surfaces as well as tool coatings were analyzed based on strip drawing experiments. The investigations have shown that the roughness of the tool surface had no effect on the resulting friction behavior within the performed strip drawing tests. However, both the tool material and its heat treatment can have an impact on the resulting tribological behavior. Furthermore, friction and wear were significantly reduced by the application of PVD-tool-coatings. Concluding, the results were successfully verified with a B-pillar-geometry in laboratory scale. It became clear, that the findings of the strip drawing experiments can be well transferred to a hot stamping process of a practical geometry.
Prof. Dr.-Ing. M. Merklein