Effect of process parameters for selective laser melting with SUS316L on mechanical and microstructural properties with variation in chemical composition

The effects of laser energy density on microstructural, mechanical properties, and chemical composition of stainless steel 316 L (SUS316L) parts fabricated by selective laser melting (SLM) technology were studied. Total 36 specimens were fabricated under the range from 1.3 to 46.7 J/mm3. The process conditions to achieve over 99.5% ± 0.1% relative planar density were obtained, and the mechanism of tunable mechanical properties was investigated by understanding the correlation between the microstructure and chemical composition according to the energy density. As the energy density increased, tensile properties were decreased with grain growth and the concentrations of light elements were increased by accelerating dissolution. As the concentrations of light elements increased, the mechanism of destructive behavior changed from ductile fracture to brittle fracture and it caused that the hardness was improved. Consequently, it was necessary to control the energy density from 9.34 to 23.98 J/mm3 in order to fabricate SUS316L parts of high strength and high elongation characteristics by SLM method.