Study on performance optimization of 316L stainless steel parts by High-Efficiency Selective Laser Melting

•The exposure time had a great influence on the densities of the SLM parts.•Properly reducing the exposure time can suppress the size of spatter balling.•Most of columnar crystals grew perpendicular to the boundary of molten pool.•The heat treatment process can improve the mechanical properties of specimens.•The building rate can reach to 12.4 mm3/s at the layer thickness of 200 μm.