The influence of 316L stainless steel powders and process parameters on the impact toughness of parts manufactured by laser powder bed fusion

316L stainless steel produced via Laser Powder Bed Fusion (LPBF) exhibits impact behavior distinct from conventionally manufactured 316L. This divergence arises from its unique microstructural characteristics. The final parts contain oxides enriched with silicon (Si) and manganese (Mn), which directly influence impact toughness. These oxides originate from the powder feedstock and/or form during fabrication. This study investigates the relationships between process parameters, raw material composition, and atmospheric conditions during LPBF fabrication and their collective effect on microstructure and impact toughness. Systematic variations in process parameters, feedstock characteristics, and fabrication atmospheres were explored. Microstructural analyses were conducted using SEM, EDS, and XRD techniques, while Charpy impact tests were performed at room temperature. The results showed that the impact toughness of LPBF 316L falls below that of conventionally manufactured 316L. Fracture surface analysis revealed a combination of ductile and brittle zones. The oxygen content and defects in the material significantly influenced impact behavior, with lower oxygen levels achieved at higher scan speeds. In contrast, slower speeds resulted in higher density but increased manufacturing defects. This research highlights the critical role of process optimization in reducing defects and improving the mechanical performance of LPBF-produced 316L stainless steel.