Stress corrosion cracking (SCC) of Fe13Cr5Ni- and Fe17Cr5.5Ni-based alloys in high-pressure/high-temperature (HP/HT) carbon dioxide (CO2) environments was investigated through slow-strain-rate tests (SSRTs) and electrochemical methods. The results show that a remarkable decrease in tensile strength and elongation to failure was observed when testing in a CO2 environment compared with that of air. Fe17Cr5.5Ni-based alloys possessed better SCC resistance than Fe13Cr5Ni-based alloys. The better SCC resistance of the former could be attributed to good repassivation capacity and pitting-corrosion resistance induced by the increase in chromium (Cr) and nickel (Ni) content.
Introduction
When service temperature exceeds 150°C, SCC resistance of Fe13Cr5Ni-based alloys could become an issue.
