Stress Corrosion Crack Growth of Pipeline Steels in NS4 Solution

Stress corrosion cracking (SCC) can occur on the soil side of buried natural gas pipelines when the coating breaks down and ground water comes into contact with the pipe surface. A neutral solution and a transgranular crack morphology have been identified with recent field cracking in Canada. A series of experiments have been conducted on fatigue pre-cracked specimens to investigate this type of SCC. Crack growth has been monitored with a direct current potential drop system and fractographic examination. The experimental system developed to investigate the growth of large stress corrosion cracks under relevant field conditions is presented and discussed.