Insight into the stress corrosion cracking mechanism of N80 carbon steel under different crevice opening dimensions in a CO2-saturated NaCl solution

The SCC of N80 carbon steel with varying crevice opening dimensions is investigated by electrochemical measurements, mechanical tests, surface analysis and hydrogen detection. The presence of a crevice structure can induce significant galvanic corrosion, leading to the formation of deep corrosion grooves and an increased hydrogen content in the steel matrix near the crevice mouth. These corrosion grooves can induce stress concentrations, thereby promoting crack initiation. Furthermore, the elevated hydrogen uptake contributes to crack propagation. Notably, the galvanic corrosion effect is exacerbated by smaller crevice opening dimensions, resulting in heightened SCC susceptibility of N80 carbon steel.