Recyclability of 304L Stainless Steel in the Selective Laser Melting Process

During part fabrication by selective laser melting (SLM), a powder-bed fusion process in Additive Manufacturing (AM), a large amount of energy is input from the laser into the melt pool, causing generation of spatter and condensate, both of which have the potential to settle in the surrounding powder-bed compromising its reusability. In this study, 304L stainless steel powder is subjected to five reuses in the SLM process to assess its recyclability through characterization of both powder and mechanical properties. Powder was characterized morphologically by particle size distribution measurements, oxygen content with inert gas fusion analysis, and phase identification by X-ray diffraction. The evolution of powder properties with reuse was also correlated to tensile properties of the as-built material. The results show that reused powder coarsens and accrues more oxygen with each reuse. The effects of powder coarsening and oxygen increase on the tensile properties of fabricated parts are being investigated.