Comparative Studies of Mechanical Properties and Microstructure of LPBF-Fabricated Virgin and Reused 316L Stainless Steel

The investigation of the various properties of components manufactured with Additive Manufacturing (AM) - methods is important to realize the implementation of recycled metals for user-end applications. This work compared the mechanical properties of virgin and recycled (green) 316L stainless steel (SS) components fabricated with Laser metal Powder Bed Fusions (LPBF). Tensile strength, Charpy-V impact toughness, and hardness tests were performed for the analysis. The specimens manufactured from the recycled 316L SS showed differences of 3–9% in hardness, 4–7% in ultimate tensile strength (UTS), and 7–8% in yield strength (YS) 0.2% compared with the virgin specimens. The difference in impact toughness between the two sets of specimens is however significant. Variations in the measurements are explained based on the studies of microstructure and phase analysis. Defects related to powders, microcracks, and compositions/phases are accountable for the differences in mechanical properties of specimens fabricated from powders of recycled metal and commercial powders. The anisotropy exhibited in the printed parts in mechanical properties and microstructure is also reported. The present work generally demonstrates that the specimens fabricated from the powders obtained from the recycled 316L SS metal can meet the standard requirements for production options and further optimization with LPBF.