Effect of heat treatment on the microstructure and corrosion resistance of 316L stainless steel fabricated by hybrid in-situ rolled wire-arc additive manufacturing

Authors：He, Youhong; Liu, Jing^*; Zhang, Shiqi; Li, Yingyu; Gao, Xiang

Source：Materials Letters, 2023, 331: 133398.

DOI：10.1016/j.matlet.2022.133398

• Additive -manufacturing
• 316L stainless steel
• Heat treatment
• Corrosion
• Microstructure

The effect of heat treatment on the microstructure and corrosion resistance of 316L stainless steel fabricated using the hybrid in-situ rolled wire-arc additive manufacturing (HRAM) technique was studied. The results showed that the as-built sample was composed of dendritic 8-ferrite and irregular austenite grains. With increasing annealing temperature (650-1200 degrees C), the corrosion resistance of HRAM 316L steel in a proton exchange membrane fuel cell environment showed a complex change trend of constant-increase-decrease-increase, attributing to the coupling effects of the variation in phase composition, grain characteristics, and texture. Particularly, after annealing at 1050 degrees C, the 8-ferrite transformed into the sigma-phase with higher contents of Cr and Mo, which promoted the formation and stabilization of the passivation film in the steel, thereby resulting in superior corrosion resistance.