Weldability of Austenitic High Mn Steels

High Mn steels (HMnS) have recently received wide and intensive attention as advanced structural materials due to their excellent combination of strength and ductility. Many studies have attempted to further improve the mechanical properties of HMnS by controlling the various alloying elements. However, the weldability of the HMnS has not been intensively studied even though mechanical properties of weld and heat affected zone are the determinant factors related to material failure, which might be critical consideration on extension of application feasibility. Thus, this research focuses on the weldability to extend the industrial applications of HMnS such as automotive, construction and shipbuilding. As a representative characteristic of weldability, the hot cracking susceptibilities of HMnS were evaluated utilizing a multiple bead Varestraint technique, and compared with those of austenitic stainless steels. In addition, the metallurgical relationship between the alloying elements (C, Mn, Al, Si, Cr, P and S), solidification behavior and microstructural evolution during welding were mainly investigated. The discussion on these results would be extensively applied to an optimization of alloy design of the HMnS for further applications.