Generation of Stress Corrosion Cracking Environments at Pipeline Surfaces

Consideration was given to how carbon dioxide (CO₂)-containing ground water, which can promote transgranular stress corrosion cracking of pipelines, can be converted to a higher pH, carbonate-bicarbonate (CO₃^2–-HCO₃^–) solution that promotes intergranular cracking of pipelines. The lower pH environment will remain only if the cathodic protection generates insufficient hydroxide ions to convert the free CO₂ to HCO₃^– and/or CO₃^2–. The generation of these ions also requires the transport of anions out of and cations into the solution contained between the pipe surface and its coating.