Abstract：321 austenitic stainless steel is widely used in the aerospace and petrochemical industries due to its excellent corrosion resistance. However, conventional manufacturing methods struggle to meet the engineering requirements for the integrated fabrication of its complex structures. In this study, laser powder bed fusion was adopted to fabricate 321 stainless steel. The regulatory laws of laser process parameters on the porosity, formability, and microhardness of the 321 stainless steels were systematically investigated to screen out the optimal forming process parameters. Furthermore, the microstructure, room-temperature tensile properties, and high-cycle fatigue properties of the 321 stainless steels prepared under the optimal parameters were systematically characterized. The results show that the 321 stainless steel fabricated under the optimal process parameters (laser power of 220 W, scanning speed of 800 mm/s, layer thickness of 0.03 mm, and hatch spacing of 0.08 mm) achieves a high relative density of 99.94%. Its microstructure exhibits a typical mixed grain structure composed of columnar and equiaxed grains, with a small amount of retained ferrite (3.5%). The 321 stainless steel possess superior tensile properties, with the yield strength and tensile strength reaching 553 MPa and 662 MPa, respectively, and the elongation being 31.9%. In addition, the fatigue limit of the material attains 530 MPa, and both tensile and fatigue failures follow the ductile fracture mechanism. This study provides an important experimental basis for the process control and engineering service of additively manufactured 321 stainless steel components.
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2026, Vol. 31 
