Effects of pre-strain on hydrogen-induced stress corrosion cracking behavior of Q345R steel in hydrofluoric acid vapor environment

This study investigates microstructure, hydrogen diffusion properties, and stress corrosion cracking (SCC) behavior of Q345R steel subject to pre-applied strains of 1 %, 3 %, and 5 %. The relationship between microstructure and SCC susceptibility in hydrofluoric acid (HF) vapor is examined. It is found that pre-strain cannot change the microstructure of Q345R steel but increases dislocation density. The increasing SCC sensitivity of Q345R steel in HF vapor is associated with the dislocation density induced by pre-strain. With increasing pre-strain, dislocation density and reversible hydrogen trap increase, and interaction between hydrogen and dislocation accelerates hydrogen-induced SCC. In addition, irreversible hydrogen traps caused by high pre-strain can severely aggravate hydrogen-induced SCC, resulting in high SCC vulnerability.