Fabrication and Process Monitoring of 316L Stainless Steel by Laser Powder Bed Fusion with µ-Helix Scanning Strategy and Narrow Scanning Line Intervals

We first fabricated the single crystal of 316L stainless steel by laser powder bed fusion (L-PBF), focusing on the applicability of the µ-Helix scanning strategy with narrow pitch as a method for obtaining a single crystal. Various combinations of laser power and laser scanning speed were examined. The cubic block samples were orientated to in the X-laser scanning direction, to in the Y-laser scanning direction, and to in the building direction, which is contrary to that obtained by the µ-Helix scanning strategy in electron beam melting (EBM), in which the X- and Y-laser scanning directions are orientated to , and Z-direction is oriented to direction. Also, it has been demonstrated that melt pool monitoring by on-axis and off-axis dual photodiodes can detect the nonequivalence of ±X-scanning and ±Y-scanning, which is responsible for the unexpected crystal orientation. Mater. Trans. 64 (2023) 1135-1142に掲載