Microstructure of 316L stainless steel formed by rolling and selective laser melting

The microstructure, microhardness, tensile properties, bending properties and corrosion resistance of 316L stainless steel formed by selective laser melting（SLM） and rolled 316L stainless steel were compared. It is found that the SLM formed stainless steel has a high forming quality on the macro level, and there are only some defects such as pores and unmelted holes. Due to the high thermal gradient of SLM manufacturing process and the high cooling rate of solidification process, the microstructure of 316 L stainless steel side formed by SLM is different from that of rolled stainless steel, which is mainly columnar crystal. Because SLM formed 316L stainless steel has a sub-grain structure, its hardness, tensile properties and bending properties are better than those of rolled stainless steel. Due to the influence of porosity, the average microhardness of the top surface is slightly higher than that of the side surface. Moreover, the corrosion resistance of SLM formed 316L stainless steel is slightly better than that of rolling forming. The results show that the SLM formed 316L stainless steel has good hardness, tensile properties,bending properties and corrosion resistance.