Effect of welding process on the microstructure and high temperature mechanical properties of RAFM steel

Reduced activation ferritic/martensite steel (RAFM) for fusion reactor was butt welded by laser welding (LBW) and tungsten inert gas (TIG) welding. The microstructures, hardness and high temperature (600℃)transient tensile properties of the welded joints were observed and analyzed. The results show that the microstructures of the two welding processes are coarse martensite, no hardening and softening of heat-affected zone occur, and the difference of tensile strength is not obvious at each temperature. In conclusion, TIG welding could provide a smaller necking area and plastic deformation, while laser welding is a more suitable choice for 3-5mm RAFM steel.