Near-Neutral pH SCC Properties of Pipeline Steels of Grade X80 and X52

Susceptibility to Stress Corrosion Cracking (SCC) of Grade X80 linepipe steels was investigated in near neutral pH conditions in comparison with conventional Grade X52 linepipes. X80 grade was manufactured by TMCP processes, whereas X52 grade was produced in controlled rolling (CR). SCC properties were evaluated by cyclic loading tensile tests in simulated solution (NS4 solution) that is typical environment for SCC under cathodic charging. Test results reveal that the Grade X80 and X52 had similar susceptibility to SCC, even the higher grade was tested under higher stress condition. It indicates that the Grade X80 have sufficient SCC resistance. This study was carried out in the High Strength Linepipe (HLP) Committee of the Iron and Steel Institute of Japan (ISIJ).