Evolution from near-neutral to high-pH environments susceptible to stress corrosion cracking: The role of sulfate and bicarbonate

Stress corrosion cracking (SCC) testing was conducted on pipeline steels to investigate the transition from near-neutral to high-pH environments via solution evaporation and concentration. The study clarified the roles of sulfate and bicarbonate in enhancing crack dissolution and their impacts on SCC. In sulfate-absent concentrated solutions, intergranular branching primarily resulted from direct propagation from the crack tip, accompanied by microcrack coalescence. The presence of sulfate effectively halted further growth by inducing crack-tip blunting, thereby reducing the mechanical driving force for crack propagation. This explanation clarifies why regions ideal for SCC exhibit no reported incidents, offering strategies for SCC mitigation.