Study of Stress Corrosion Cracking Resistance and Hydrogen Embrittlement of X70 and X80 Steels with a Novel Approach Oil and gas transmission pipelines operating in corrosive environments are susceptible to severe failures caused by stress corrosion cracking (SCC) and hydrogen embrittlement (HE). This reaserch investigates the effect of hydrogen uptake on the corrosion behavior of X70 and X80 pipeline steels using a novel approach. Based on this, hydrogen anodic oxidation, potentiodynamic polarization, and slow strain rate testing (SSRT) tests were conducted to determine the resistance to SCC and HE. The results indicate that hydrogen absorption in X80 (2.2 ± 0.1 mol/m3) is significantly higher than that in X70 (0.86 ± 0.01 mol/m3) at a charging current density of -10 mA/cm². In addition, the SCC cross-sectional sensitivity index was determined to be 51.5% for X80, whereas this parameter was calculated to be only 1% for X70. The analyses reveal that the tougher microstructure of X70 exhibits superior resistance to hydrogen ingress and SCC crack propagation, while X80 shows a higher sensitivity to brittle fracture. These findings confirm the superiority of X70 alloy for applications in hydrogen-rich environments.

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