Impact of strain on the corrosion resistance of 304 stainless steel welded joints using electrochemical methods and numerical modeling of stress corrosion

Abstract

This study explores the effect of strain on the corrosion resistance of 304 stainless steel welded joints through electrochemical testing while also presenting a novel pitting model that accounts for the influence of stress and strain on pit growth behavior. Initially, bending experiments and open circuit potential tests were conducted on the welded joints, revealing that compressive stress increases the open circuit potential, while tensile stress decreases it. Subsequently, tensile tests and polarization curve assessments demonstrated that laser oscillating welding enhances both the tensile strength and corrosion resistance of the joints, outperforming traditional laser welding. The measured corrosion potentials were −0.25 V and −0.27 V, shifting to −0.34 V and −0.35 V after the tensile tests. Additionally, finite element simulations based on the Arbitrary Lagrangian-Eulerian method were used to model pitting corrosion propagation. The results indicated that pitting corrosion leads to uneven stress distribution and localized plastic deformation, with its development closely linked to the material's stress state. This results in increased stress as pits grow, consistent with the mechano-electrochemical (M-E) effect.