Stress corrosion damage on austenitic stainless steel in sodium chloride

Abstract

The aim of this work is to present the corrosion damage mechanism of austenitic stainless steel 304. The C-ring specimens are chosen according to ASTM G-38 to resemble the stress conditions during the applied load. The specimens are immersed in 3.5% wt of NaCl solution. The variable conditions were studied at a fixed stress of 379Mpa and immersions for 720 hours. The stress distribution over the surface of specimens is formulated by means of a finite-element analysis. The result of the finite-element analysis shows that the region that was perpendicular to the shift in the direction of the pressure was subjected to the highest load. Using the potentiodynamic polarisation measurement method and microscopic observation, the corrosion polarisation behaviour of austenitic stainless steel became more active in cases when immersion and stress are applied simultaneously. The stress on the surface of the specimen shows a significant effect on the polarisation mechanism in the analysed area. The result also shows that the locations of pitting corrosion are apparent on the highest stress area. There is useful information to analyse the corrosion behaviour especially for applications under mechanical loading in corrosive environments, it drives the corrosion behaviour to the critical condition.