Effect of strain rate and potential on the propagation of stress corrosion crack

On the basis of the model of slip-bare metal dissolution-repassivation and crack-tip strain analysis, a theoretical equation of stress corrosion crack propagation rate as a function of crack-tip strain rate and potential for 304L stainless steel in acidic chloride solution was deduced. The theoretical prediction showed that there are two regions in the curve of crack propagation rate with the crack-tip strain rate. In region I, the crack growth rate increased with increasing crack-tip strain rate. In region 11, the crack propagation rate was independence of the crack-tip strain rate. The crack propagation rate of 304L stainless steel in acidic chloride solution has been measured by slow strain rate testing (SSRT) technique. The crack propagation rate calculated theoretically was consistent with the experimental results in region 11 when potential was controlled in anodic region.