Effect of H₂S concentration on stress corrosion cracking behavior of 35CrMo steel in an artificial solution simulated drilling well waters at oil field

The corrosion behavior and stress corrosion cracking (SCC) of 35CrMo steel were examined respectively by means of electrochemical measurements and slow strain rate tensile test in an artificial solution with various concentration of H₂S, which aimed to simulate the drilling well environments at oil field. It is shown that 35CrMo steel exhibits a susceptibility to SCC in hydrogen sulfide solutions with pH=5. The susceptibility increases by decreasing the concentration of H₂S. When the concentration of H₂S reached 200 mg/L, the corrosion electrochemical process of 35CrMo steel can be promoted, whilst the steel exhibits obvious susceptibility to SCC. The SCC of 35CrMo steel is mainly induced by hydrogen embrittlement (HE) process associated with anodic dissolution (AD) in hydrogen sulfide solutions with pH=5.