A comparative study on the preparation of 316L stainless steel via additive manufacturing and vacuum arc melting

Additive manufacturing (AM) offers unique capabilities for producing high-performance alloys with refined microstructures. Here, 316L stainless steels fabricated by AM and conventional vacuum arc melting (VAM) were systematically compared in terms of microstructure, defects, and mechanical response. The AM steel exhibited a 49% increase in hardness and a 29% improvement in ultimate tensile strength relative to the VAM steel, while its defect volume fraction was reduced to one-third. Both processing routes generated Si–Mn–O inclusions; however, the AM material uniquely contained a high density of nanoscale second-phase particles that contributed to strengthening. Thermodynamic modeling (FactSage) and molten pool simulations (ProCAST) revealed the role of rapid solidification and thermal gradients in promoting nanoscale precipitation and defect mitigation in AM. These findings demonstrate that AM not only tailors defect characteristics but also enables microstructural refinement, thereby offering a pathway to superior mechanical performance compared with conventional melting techniques.