LAUSR

Advanced High Strength Steels (AHSS) are most popular car body material in the current automotive industry, since they can reduce the automobile body weight without compromising safety.1,2) Moreover, the current tendency of AHSS have been developed into low density, high strength, and high ductility. In recent years, a new generation of high strength and high ductility Medium-Mn steel has been successfully developed due to excellent properties with regard to the strength-ductility balance.3,4) Multi-phase, meta-stability, and multi-scale microstructure is obtained by austenite reverted transformation (ART-annealing) or Quenching and Partitioning (Q & P).5–7) High strength of the steel is obtained through phase transformation strengthening and grain refinement strengthening.4,8) High ductility of Medium-Mn steel is achieved by the effects of transformation induced plasticity (TRIP) of metastable austenite during Microstructure and Mechanical Properties of Simulated Heat Affected Zone of Laser Welded Medium-Mn Steel