SCC of X70 pipeline steel in Yingtan acid soil environment

In order to study the SCC susceptibility and obtain basic data for corrosion protection of X70 pipeline steel in the acid soil environment of Yingtan, China, slow strain rate test (SSRT) and polarization curves were used to studied the SCC of X70 steel. SCC did occur to the as-received material, with a transgranular cracking mode charged with different cathodic potential. The applied cathodic polarization potential played an important role in facilitating the occurrence of SCC. X70 pipeline steel was little sensitive to SCC in an anodic potential condition, but as the applied cathodic potential went down, a combined electrochemical reaction of anode and cathode or a cathode process at even lower potential controlled the corrosion behaviour of X70 steel, and SCC took place.