Stress corrosion cracking behavior of pipeline steel X60 in near-neutral pH soil environments around Shanghai

Near-neutral pH stress corrosion cracking (SCC) behavior of pipeline steel X60 in typical soil environments around Shanghai has been investigated for structural integrity assessment. The effects of soil type and electrode potential from cathodic protection point were evaluated through slow strain rate tests (SSRT) at various electrode potentials in three solutions containing different typical soils. Results showed that the SCC susceptibility generally increased with decreasing electrode potential in all the three environments, with quick increase happening in the range of -1200 similar to -700mV(SCE). It is suggested that hydrogen induced cracking should dominate the SCC at low potentials. In cathodic potential range, the rank of the SCC susceptibility for soil type was Near-city soil > Cyan-purple soil > Cyan-yellow soil. In anodic potential range, SCC susceptibility curves mixed each other in the three solutions.