Stress corrosion cracking behavior of rusted X100 steel under the combined action of Cl- and HSO3- in a wet-dry cycle environment

X100 steel is an important material used to construct marine pipelines; hence, understanding its stress corrosion cracking (SCC) behavior is important. Herein, we investigated the SCC mechanism of rusted X100 steel in a wet-dry cycle environment at various Cl- and HSO3- contents. Slow strain-rate testing revealed brittle fracture features at high HSO3- content, while electrochemical studies showed that HSO3- promotes increased cathode current density that contributes to stress corrosion cracking. We conclude that SCC cracking is initiated at pits formed by anodic dissolution, while the hydrogen-evolution mechanism dominates in a high HSO3- concentration environment.