A review of stainless steels additive manufacturing: Microstructural features, mechanical behavior, and associated challenges and solutions

Additive manufacturing (AM) enables the fabrication of complex and customized stainless steel components that are often unattainable by conventional subtractive or casting routes. Among the various alloys, austenitic stainless steels—particularly 316L—have been most widely studied due to their good printability, mechanical robustness, and corrosion resistance. In parallel, ferritic and duplex stainless steels are increasingly being explored to meet application-specific demands. This review systematically summarizes the current state of stainless steel AM with a focus on the relationships between process parameters, microstructural evolution (porosity, phase distribution, grain morphology, and defects) and resulting mechanical properties (strength, ductility, fatigue, and hardness), as well as corrosion behavior. Special emphasis is placed on laser powder bed fusion (LPBF/SLM), directed energy deposition (DED/LMD), wire arc additive manufacturing (WAAM), and binder jetting, and on how their process characteristics compare with conventional wrought and cast products. Compared with previous reviews that mainly address metal AM in general or focus predominantly on 316L, this work provides a stainless-steel-specific and process-resolved comparison, including quantitative data tables and a consolidated mapping of key challenges—such as porosity, residual stress, anisotropy, surface roughness, and corrosion—and their corresponding mitigation strategies. The critical analysis highlights current limitations that still hinder full-scale industrial deployment and identifies promising directions for further research and process optimization.