In this study, 316L austenitic stainless-steel (ASS) plates fabricated using an additive
manufacturing (AM) process were joined using tungsten inert gas (TIG) and laser welding techniques.
The 316L ASS plates were manufactured using a laser powder bed fusion (LPBF) technique, with
building orientations (BOs) of 0◦ and 90◦, designated as BO-0 and BO-90, respectively. The study
examined the relationship between indentation resistance and microstructure evolution within the
fusion zone (FZ) of the welded joints considering the effects of different BOs. Microstructural analysis
of the weldments was conducted using optical and laser confocal scanning microscopes, while
hardness measurements were obtained using a micro-indentation hardness (HIT) technique via the
Berkovich approach. The welded joints produced with the TIG technique exhibited FZs with a greater
width than those created by laser welding. The microstructure of the FZs in TIG-welded joints
was characterized by dendritic austenite and 1–4 wt.% δ-ferrite phases, while the corresponding
microstructure in laser-welded joints consisted of a single austenite phase with cellular structures.
Additionally, the grain size values of FZs produced using the laser welding technique were lower than
those produced using the TIG technique. Therefore, TIG-welded joints showcased hardness values
lower than those welded by laser welding. Furthermore, welded joints with the BO-90 orientation
displayed the greatest cooling rates following welding processing, leading to FZs with hardness
values greater than BO-0. For instance, the FZs of TIG-welded joints with BO-0 and BO-90 had
HIT values of 1.75 ± 0.22 and 2.1 ± 0.09 GPa, whereas the corresponding FZs produced by laser
welding had values of 1.9 ± 0.16 and 2.35 ± 0.11 GPa, respectively. The results have practical
implications for the design and production of high-performance welded components, providing
insights that can be applied to improve the efficiency and quality of additive manufacturing and
welding processes. |
