Qualification of 6% Mo Stainless Steel: Alignment with ISO 15156

Abstract Corrosion resistant alloys are widely used in the industry as a subsidy for Carbon steel exposed to higher corrosive environments. This study evaluates the pitting and corrosion behavior of Super austenitic stainless steels containing 6% molybdenum (6% Mo stainless steel such as UNS S31254) simulated for actual project operating conditions under a case scenarios. For this case study, the testing condition is in accordance with ISO 15156 limits; however, exceeds the limits defined by PDO’s internal specifications. Therefore, the objective is to qualify the current condition for organizational specification limits. The testing would be carried at a temperature of (100°C) and chloride concentrations of (30,000 mg/l), given a CO2 mol% of 16% and partial pressure of H2S is 400kPa. Four-point bend test (FPB) would be carried in accordance with NACE TM 0316 for triplicate samples collected from as -welded samples from a 12’’, 20’’ and 24’’ spools