The influence of chemical composition and microstructure of API linepipe steels on hydrogen induced cracking and sulfide stress corrosion cracking

The chemical composition and microstructure are known to have a significant effect on the resistance to hydrogen induced cracking (HIC) and sulfide stress corrosion cracking (SSCC) of structural steels in wet H2S environments. In this paper, the influence of microstructure on HIC and SSCC behavior of two low C–Mn–Nb–Mo API linepipe steels has been investigated. Subjecting the steel to different thermomechanical processes modified the microstructure. The results showed that refined and homogeneous quenched and tempered bainite/martensite microstructures had the best performance with respect to both HIC and SSCC susceptibility.