Effect of Elastic Tensile Stress on the Pitting Corrosion Mechanism And Passive Film of 2205 Duplex Stainless Steel

Abstract

The effect of elastic tensile stress on the pitting corrosion mechanism and passive film of 2205 duplex stainless steel (DSS) in NaCl solution containing sulfide ions are investigated. The results reveal that as the elastic tensile stress increases, the pitting corrosion sensitivity of 2205 DSS first decreases and then gradually increases, which is attributed to the changes in the chemical state, thickness, and micro-defects of passive film. Furthermore, the initial pits occur at austenite phase under low elastic stress but at ferrite phase under higher elastic stress. The corrosion pits grow faster along the pits bottom direction and the perpendicular direction of tensile stress.

Keywords: Duplex stainless steel, Elastic tensile stress, Passive film, Pitting corrosion, Corrosion mechanism