Role of the microstructures on uniform corrosion and SCC behavior of high-strength low-alloy steels

Uniform corrosion and stress corrosion cracking (SCC) of high-strength low-alloy steels with different microstructures in marine environment were investigated. The results show that microstructures (granular bainite, granular bainite and ferrite and tempered sorbite) significantly affect the uniform corrosion rate and SCC susceptibility, but the order of the effect of the microstructures on the two kinds of corrosion is different. Microstructures change the γ-FeOOH proportion of the rust layer, which determines the protection performance and corrosion rate. Hydrogen embrittlement, one of SCC mechanisms, is highly related to the microstructures, i.e., the dislocation density, high-angle grain boundary proportion and Taylor factor value.