Behavior of type 304 and type 316 austenitic stainless steels in 55% lithium bromide heavy brine environments

Cylindrical tensile specimens of AISI type 304 (UNS S30400) and type 316 (UNS S31600) stainless steels (SS) were tested under constant-load conditions in 55% lithium bromide (LiBr) heavy brines at temperatures of 120 °C and 140 °C. Elongation and open-circuit potential (OCP) were recorded during the tensile test. Potentiodynamic polarization measurements were conducted, and the failed surface fractures were examined by scanning electron microscopy. The tested SS were subjected to stress corrosion under the test environments. Sensitivity was affected strongly by pH values. In LiBr brine of pH = 11.6, the passivation processes were more effective than in brine of pH = 6 to approximately 8. Because of effective passivation behavior in brine of pH = 11.6, lower values of ΔI₀ were measured, indicating lower dislocation relaxation processes and high resistance to stress corrosion cracking.