H2S浓度对35CrMo钢应力腐蚀开裂的影响

Effect of H_2S Concentration on Stress Corrosion Cracking Behavior of 35CrMo Steel in An Artificial Solution Simulated Drilling Well Waters at Oil Field

用电化学技术研究了35CrMo钢在含有不同浓度H2S溶液中的腐蚀行为,通过慢应变速率拉伸实验研究了35CrMo钢在不同浓度H2S介质中的应力腐蚀开裂(SCC)行为与机理。结果表明:35CrMo钢在pH值为5的H2S环境下存在SCC敏感性,H2S浓度升高,SCC敏感性增加,H2S浓度为200 mg/L时有明显的SCC敏感性。H2S浓度达到200 mg/L时,能明显促进35CrMo钢腐蚀电化学过程进行。在pH值为5的H2S环境下,35CrMo钢的SCC机制是以氢脆(HE)为主,阳极溶解(AD)为辅的协同机制。

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.