Stress corrosion cracking behaviour of 316L stainless steel exposed to CO2–H2S–Cl− environments in the absence and presence of methyldiethanolamine (MDEA)

Abstract

Stress corrosion cracking (SCC) behaviour of 316L stainless steel in CO2–H2S–Cl− environments with and without methyldiethanolamine (MDEA) was investigated by slow strain rate testing and scanning electron microscopy (SEM). The results show that elongation ratio, reduction in area ratio (RAR) and time to failure ratio (TTFR) of 316L stainless steel were low in CO2–H2S–Cl− environments. The corresponding fractography exhibited flat brittle fracture with quasi-cleavage pattern, indicative of high SCC susceptibility. Hydrogen penetration and corrosion pits could be responsible for the high SCC susceptibility of 316L stainless steel in this condition. For the CO2–H2S–Cl− environments in the presence of MDEA, 316L stainless steel possessed high ER, RAR and TTFR (nearly 100%). High SCC resistance of 316L stainless steel could be associated with MDEA induced removal of H2S/CO2 and absorption on the steel surface.