Mechanistic aspect of stress corrosion cracking of X80 pipeline steel under non-stable cathodic polarization

In this work, the square wave polarization (SWP) technique and slow strain rate tensile test were combined to investigate the influence of cathodic potential fluctuation, i.e. the non-stable cathodic polarization, on the electrochemical and stress corrosion cracking (SCC) behavior of X80 pipeline steel in an acidic soil solution. It was found that the non-stable cathodic polarization accelerated both the anodic dissolution and the cathodic hydrogen evolution, inducing the increase of SCC susceptibility compared with the potentiostatic cathodic polarization. This provides a novel and important concern and recommendation for controlling pipeline SCC under CP fluctuation.