Effects of Residual Tensile Stresses on Electrochemical Corrosion Behavior of 304 Stainless Steel

The 304 stainless steel was processed into U-bend specimen and unloaded, and then the residual stresses at the tensile surface after unloaded were tested. The electrochemical corrosion behavior at the tensile surface of U-bend specimens with different curvature radii (i.e. different residual tensile stresses) in dilute sulphuric acid solution was also studied. The results show that the residual stresses at the tensile surface of U-bend specimen after unloaded were tensile stresses, and the residual stress increased with the decrease of the curvature radius. With the increase of the residual tensile stress, the initiating passivation current density and the passive current density of the specimen increased, while the repairing ability of the passive film weakened, resulting in the decrease of the pitting corrosion resistance. The dislocation density was a relatively high due to the relatively large residual tensile stress, resulting in a relatively large corrosion current.