Hydrogen Induced Cracking of API X52 and X60 Sour Service Steels Subjected to Pre-Strain under Prolonged H2S Exposure

Abstract

The effect of plastic deformation on API X52 and X60 sour service steels on hydrogen induced cracking was studied. Plastic deformation was performed with a tensile pre-strain with the percentage variation of strain. The HIC test was carried out with a duration of 168 hours of hydrogen charging to investigate the cracking behavior. After hydrogen charging, the cross sections of both steels were observed to find out hydrogen cracks. Ultrasonic testing was carried out on the specimen surface to see the distribution of laminated cracks. The hydrogen crack surface was observed using SEM. The results showed that the values of CSR, CLR and CTR increased with increasing percentage of pre-strain. Ultrasonic testing showed that the area influenced by HIC increased with increasing percentage of pre-strain. The susceptibility of API X52SS and X60SS to HIC increases with increasing percent of pre-strain. API Steel X52SS has better HIC resistance than X60SS on high pre-strain.