Effects of H₂S/HS⁻ on Stress Corrosion Cracking Behavior of X100 Pipeline Steel Under Simulated Sulfate-Reducing Bacteria Metabolite Conditions

The effect of H₂S/HS⁻, which simulates the main metabolites of sulfate-reducing bacteria (SRB), on the electrochemical and stress corrosion cracking (SCC) behaviors of X100 steel was investigated in a near-neutral solution. The results showed that different H₂S/HS⁻ contents mainly affected the cathodic process of X100 electrochemical corrosion. As the concentration of H₂S/HS⁻ increased, the corrosion potential was shifted negatively, the corrosion current density was considerably increased, and the corrosion rate was linearly increased. Different rust layers with shifting structures were formed under different conditions and had different effects on electrochemical behaviors. However, sulfide mainly promoted local corrosion processes. With the synergistic effects of stress and H₂S/HS⁻, SCC susceptibility was considerably enhanced. The accelerated process of hydrogen evolution by sulfide was crucial in enhancing SCC processes. In brief, the trace H₂S/HS⁻ generated by SRB metabolites played a positive role in promoting SCC.