Corrosion behavior of 316L and HR-2 stainless steels in ferric chloride solution

The corrosion behavior of stainless steels 316L and HR-2 in ferric chloride solution was investigated by immersion method, electrochemical test, scanning electrochemical microscopy (SECM) , slow strain rate tensile test (SSRT) and stress corrosion cracking (SCC) test. The results demonstrate that the corrosion resistance of both HR-2 SS and 316L SS without stress is better, only 316L SS is slight sensitive to pitting. However, under dynamic tensile stress, the SCC susceptibility of the two steels is high. This is because dynamic tensile stress promotes the rupture of surface passive film, and accelerates the initiation and propagation of SCC crack. 316L SS exhibited more sensitive to SCC than HR-2 SS, which is due to the pitting susceptibility of 316L is higher, thereby, the passive film on 316L can be destroyed easily under dynamic tensile loading.