Anti-H₂S stress corrosion cracking performance of X65 pipeline steel welded joint

As the submarine pipeline, especially its weak locations like welded joints, etc are subjected to H₂S stress corrosion cracking risk in operation process, therefore, the anti-hydrogen bubbling (HB) and hydrogen-induced cracking (HIC) and sulfide stress corrosion cracking (SSCC) performance tests are performed according to relevant NACE standards, and the generation mechanism of SSCC is discussed. The results show that X65 pipeline steel welded joints have excellent resistance to H₂S stress corrosion. If the applied stress is 90% of average yield strength, the initiation of SSCC will appear on the sample surface. The SSCC mechanism under the test conditions is the mixed mechanisms of anodic dissolution and hydrogen embrittlement (AD+HE mechanism), and at the same time, the SSCC sensitivity is under the greatest influence of pH, temperature and stress. If the pipeline laying is qualified, the submarine pipeline will be subjected to small risk of sulfide stress corrosion cracking (SCC) under current operation conditions.