Effect of Laser Spot Size, Scanning Strategy, Scanning Speed, and Laser Power on Microstructure and Mechanical Behavior of 316L Stainless Steel Fabricated via Selective Laser Melting

Selective laser melting (SLM) is a promising additive manufacturing process for fabricating complex geometries of metallic parts. The SLM processing parameters can have a major effect on microstructure and mechanical behavior of the fabricated metallic parts. In this work, the effect of laser spot size, hatch spacing, energy density, scan strategy, scanning speed and laser power on the microstructure and mechanical behavior of SLM-processed 316L stainless steel samples has been studied. These samples processed with different processing parameters were characterized by performing microhardness, tensile tests, x-ray diffraction (XRD) analysis, Energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) analysis. The samples fabricated with a larger laser spot size exhibited higher tensile strength as well as higher microhardness values. A similar trend was observed for samples processed with higher laser power and hatch spacing. For the same energy density, higher laser power and lower scanning speed significantly enhance the mechanical properties of SLM processed samples compared to those fabricated with lower laser power and higher scanning speed. Therefore, it can be concluded that laser power has a more dominant role in governing the mechanical properties of SLM processed parts than scanning speed.