Cold surface hardening

Cold surface hardening merges the properties of specially heat-treated high-alloyed steels with structural changes induced by mechanical processes such as deep rolling. Compared to conventional transformation-induced plasticity- (TRIP-) steels these materials show noticeably better machinability because the generated austenitic structure is stable enough to avoid transforming during cutting processes. As a result of the mechanical stresses applied by a deep rolling tool after machining, martensitic transformation occurs in the surface layer to a depth up to 0.5–0.6 mm. The advantages of this innovative approach include the elimination of thermal hardening and the combination of hardening and surface finishing in one step which is performed on the same machine tool. Less distortion and economical savings are further advantages of this new manufacturing technology.