A novel medium-Mn steel with superior mechanical properties and marginal oxidization after press hardening

A novel Cr-alloyed medium-Mn steel was designed and manufactured for the hot forming application in automobile. Compared to typical press hardening (PHS) grade of 22MnB5, it possesses more excellent mechanical combination enormously reduced oxidization after hardening. The synchrotron-based high-energy X-ray diffraction experiment indicated that solute C atoms could be partitioned from martensite austenite during baking process then segregated on geometry necessary dislocations had been generated due austenite-to-martensite transformation previous cooling. This led much hardened grains, which bear load accommodate greater deformation until they transformed than non-baked thus greatly improving both strength ductility. Moreover, thickness layer invented is less 3 ?m at 750?810°C, thinner 100 ?m-thick 22MnB5. Such a tremendously oxidation results lower soaking temperature employed formation dense Cr/Al/Si oxide band bottom layer, latter because contains higher contents Cr Al