Effect of annealing on the mechanical and corrosion properties of 316L stainless steel manufactured by laser powder bed fusion

The effect of annealing on the mechanical and corrosion response of 316L stainless steel produced using laser powder bed fusion (LPBF) was investigated. The as-printed materials were subjected to annealing at a temperature of 1000 degrees C for 2 h. Microstructural observations revealed that after annealing the cellular network inside the grains disappeared, and a slight increase in grain size and the proportion of low-angle grain boundaries (LAGBs) occurred. The most significant microstructural changes occurred with the nano-inclusions, as the annealing resulted in change in their chemical composition, a decrease in their density (number per unit volume), while simultaneously their size increased. All these changes caused a decline in the mechanical properties of the steel and an increase in its susceptibility to localized corrosion.