PERFORMANCE EVALUATION OF AISI 316L AND SUPER DUPLEX AISI F53 STAINLESS STEELS REGARDING CREVICE CORROSION

摘要

This paper presents the results of tests conducted with the objective of verifying the crevice corrosion resistance of AISI 316L austenitic stainless steel and AISIF53 super duplex stainless steel. Specific tests were conducted in order to simulate external corrosion condition of offshore oil extraction pipelines, where synthetic sea water with bubbling atmospheric air was tested, which intent to simulate shallow water immersion condition, where the seawater is very aerated because of natural waves and splashes. Additionally, field tests were conducted through exposition of metallic coupons directly in natural sea water as well as electrochemical tests according to ASTM G 61. The immersion tests in seawater showed that the AISI 316L austenitic stainless steel and AISI F53 super duplex stainless steel are susceptible to crevice corrosion, and this susceptibility is highly dependent on the surface finishing. Laboratory tests can be used to access the susceptibility of crevice corrosion for AISI 316L but not for AISI F53.