Effects of Gas-Tungsten Arc Welding on the Mechanical Properties and Microstructure of 316L Stainless Steel by Powder Bed Fusion

Abstract

This paper investigates the weldability of stainless steel 316L and tensile behavior of welded samples, comparing in samples produced through powder bed fusion (PBF) and the conventional wrought method. Tensile testing is performed on each welded combination of materials (PBF-PBF, wrought- wrought, and PBF-wrought). Results suggest that the wrought material exhibits higher tensile strength and uniform elongation point, while displaying a lower yield stress compared to the PBF material. Additionally, welded wrought samples have a significantly lower tensile strength compared to non-welded samples. The wrought samples exhibit a larger average grain size in the heat affected zone (HAZ) compared to non-heat affected regions. In contrast, it is found that grain coarsening does not occur in PBF samples, which exhibit a significantly smaller grain size in the HAZ than the wrought samples. The average grain size in the non-heat affected zone is larger for the PBF samples compared to the wrought samples. Larger grain sizes within the HAZ correspond to a reduction in tensile strength and uniform elongation point for the wrought samples, compared to PBF samples. However, no such reduction is observed for the PBF samples. Secondary dendrite arm spacing measurements indicated similar solidification behavior in the weld regions of both PBF and wrought materials. Overall, the PBF samples exhibit less reduction of strength and ductility after welding than wrought samples. Therefore, it is determined that additively manufactured 316L stainless steel has a higher weldability than traditionally manufactured wrought 316 stainless steel.