Frictional and thermal behavior of tool materials and tool coatings for press hardening

Hot sheet metal forming is gaining in importance in many fields, because of its capabil-ity to produce more complex components than possible with cold forming. Hot forming is also used to influence the final material properties with the hot forming of manganese boron steels being a good example. One of the major challenges in hot forming is the tribological conditions between the tool and sheet material at the required high tempera-tures. This article will discuss the influence of different tool material coatings, ranging from PVD to mechanically bonded ceramic coatings, on the tribological conditions dur-ing forming. It will also shed light on how these coatings influence the heat transfer by quenching experiments and cyclical tests in comparison to typical press hardening tool steels (HTCS 130, GTCS 550) and an oxide ceramic.