Stress Corrosion Cracking Behavior of X80 Steel in Artificial Seawater Under Controlled Strain Rate and Applied Potentials

Abstract

The effect of applied potential on the stress corrosion cracking (SCC) behavior of X80 steel was examined in artificial seawater (ASW) at different strain rates of 1x10(-4), 1x10(-5) and 1x10(-6)/sec. The controlled potential of -650, -850, -950 and -1,050 mV(SCE), respectively, was applied during strainig. It was found that X80 steel was susceptible to SCC in seawater environment under both anodic and cathodic applied potentials and the susceptibility was sensitive to strain rate. The SCC was initiated at the surface pits under an anodic applied potential of -650 mV(SCE). The effect of cathodic applied potential on the SCC behavior of X80 steel in ASW was more complex, such that the combined effect of surface damage, including pits and hydrogen-induced cracking, and hydrogen concentration generated on the surface tended to determine the SCC susceptibility. The SCC behavior of X80 steel with different applied potentials in ASW was discussed based on the microstructural and the fractographic observations.