Effect of SO2 content on SCC behavior of E690 high-strength steel in SO2-polluted marine atmosphere

Slow strain rate tensile (SSRT) test in a simulated device was employed to investigate the effect of SO2 on stress corrosion cracking (SCC) behavior of E690 steel in SO2-polluted marine atmosphere. Results revealed that SO2 can greatly enhance the SCC susceptibility of E690 steel in marine atmosphere and the SCC mechanism in this environment is a combination of anodic dissolution (AD) and hydrogen embrittlement (HE). The increase of SCC susceptibility was attributed to the formation of a compact rust layer on steel surface that SCC microcracks can initiate from the bottom of cracks in the rust layer consequently. Moreover, hydrogen evolution was greatly enhanced with the increase of SO2 content, and SCC susceptibility increased rapidly as a result.