Large area of cracks and leakage were found on some welded stainless steel pipes. The pipes were analyzed by means of macroscopic examination, chemical composition analysis, metallographic examination, SEM and EDS. The results showed that the crack was stress corrosion cracking caused by chloride ion. The stress corrosion was due to the combined effects of residual stress which was caused by no heat-treatmnet after cold-working and chloride ion which came from rubber insulation material.
