Pitting Resistance Evaluation of Stainless Steel Alloys in Presence of Neat Production Chemicals by Using Accelerated Electrochemical Tests

摘要

This paper proposes a novel approach to evaluate pitting resistance of austenitic and super duplex stainless steel in contact with typical corrosion inhibitors used in the oil and gas industry. In this study, accelerated electrochemical tests are used instead of conventional immersion tests to determine the compatibility of neat chemicals with different metallurgies. A modified version of the standard ASTM G611 and G1502 ASTM tests are used. Two neat corrosion inhibitors instead of the standard 1M NaCI solution were used as electrolytes and the ASTM G611 and ASTM G1502 electrochemical tests were run in order to find a correlation with actual operating conditions. Critical Pitting Temperature (CPT) of about 85°C and 76°C were obtained for SS304 in presence of Inhibitor A and Inhibitor B, respectively. CPTs greater than 80°C were reported for SS316L, SS317L, and SDSS2507 stainless steel materials immersed in both inhibitors A and B. Traditional immersion test may not reveal the susceptibility to pitting corrosion of a chemical in contact with a determined metallurgy. Alternatively the use of modified accelerated electrochemical tests have been demonstrated to be a quick and conservative screening tool when evaluating compatibility of neat chemicals with typical field metallurgies at actual field operating conditions.