Microstructure and mechanical properties of 304L stainless steel processed by selective laser melting

304L stainless steel was prepared by selective laser melting (SLM) technology. The microstructure, morphology and mechanical properties of as-fabricated parts were characterized. The results show that no obvious pores and inclusion defects are found in the metallographic structure. The surface roughness of the sample decreases with the increase in the inclination angle during the SLM process. To keep the geometrical characteristics of as-fabricated SLM parts, the thickness of thin-walled specimen should be more than 0.3 mm; the diameter of circular hole without support should be controlled in the range of 1 mm to 12.5 mm; the designed outer sharp angles of the specimen should be more than 5°; the inner sharp angles should be more than 15° when placed vertically to the base plate, and more than 8° when placed horizontally. It is found that the orientation of the specimen axis with respect to the working platform does not influence the tensile strength and yield strength. When the build direction of the specimens is 0° with the base plate, the maximum tensile strength of the specimens reaches 684.7 MPa. When the build direction was 30° with the base plate, the maximum post-fracture elongation of the specimens reaches 47.7%. Meanwhile, the impact energy has the maximum value of 196.3J, and the fracture mechanism is ductile fracture. © 2019, Jilin University Press. All right reserved.