Pitting behavior of SLM 316L stainless steel exposed to chloride environments with different aggressiveness: Pitting mechanism induced by gas pores

In this study, the pitting behaviors of wrought and SLM 316L SSs (stainless steels) are comparatively investigated under the conditions of different aggressiveness. The experimental results show that SLM 316L SS exhibits higher sensitivity to pitting corrosion in extremely aggressive solutions, while the wrought sample is more vulnerable to pitting in conditions with low aggressiveness. Gas pores are the pitting-sensitive sites in SLM 316L SS, and metastable pits initiated at covered gas pores are easier to evolve to stable growth compared to open pores due to the greater diffusion resistance.