Corrosion Behavior of Spiral Welded X60 Pipes in Wet H₂S Environment

The H₂S corrosion behavior of over bending and under bending formed spiral submerged arc welded steel pipes in NACE solution has been investigated by use of the self designed full scale pipe corrosion test unit.Results indicate that the H₂S damage of welded pipes shows blister and stress corrosion cracking(SCC) in pipe surface.The H₂S corrosion trend increases with the increase of applying stress and residual stress.The damage mechanism of the welded pipes in H₂S containing solution under the presence of applying stress and residual stress has not only hydrogen induced cracking(HIC),but also stress corrosion cracking,and the applying stress and residual stress promote not only stress corrosion cracking,but also hydrogen induced cracking.The test results reveal that improving pipe surface quality especially weld surface quality,lowering tensile residual stress and controling operating stress are the key measures for controlling the wet H₂S corrosion of welded steel pipes.