Analysis of Leakage Accident of L360MCS Longitudinal Submerged Arc Welded (LSAW) Pipe

The leakage accident occurring in a 508 mm×16mm L360MCS LSAW (longitudinal submerged arc welded) pipe was investigated by testing the pipe material composition, analyzing the metallograph and smicro morphology of the fracture. The results showed that the leakage of the pipe was caused by sulfide stress corrosion cracking. The surface scratch martensite and high residual stress due to unproper repairing welding process could increase the susceptibility to sulfide stress corrosion cracking of the weld.