Effect of Potential on SCC Initiation for Pipeline Steel in near-Neutral PH Solution

The effect of applied potential on the stress corrosion cracking (SCC) initiation of X-70 pipeline steel in near-neutral pH solution has been investigated by using a slow strain rate testing (SSRT) apparatus and electric potential drop (EPD) method. It was found from the SSRT results that the initiation stress decreased with the decrease in the potential from -790mVSCE to -950mVSCE. But the initiation stress increased when the applied potential was at -1100mVSCE and then decreased at -1200mVSCE. The initiation stress also decreased when the anodic potentials were applied to the samples. SEM observations favored the above SSRT results.