Corrosion morphology evolution and numerical modeling of Q500qENH weathering steel welds under salt-spray exposure

Abstract

To investigate the corrosion evolution of Q500qENH welded joints in a neutral salt-spray environment, 36 butt-weld specimens were subjected to corrosion tests for 20 d, 40 d, and 60 d. The macro- and microscopic characteristics of the corroded surfaces, along with the mass loss variation curves, were obtained to analyze the progressive corrosion behavior of the heat-affected zone (HAZ) and base material. Using noncontact surface morphology measurements and MATLAB-based statistical analysis, key pit parameters, such as pit depth and depth-to-diameter ratio, were extracted to characterize the evolution of corrosion morphology. The reliability of the pit depth extraction algorithm was verified by comparing its results with actual depths measured using a 3D profilometer. Additionally, a numerical reconstruction approach, integrating statistical modeling with secondary development in ABAQUS, enabled the simulation of corrosion pit initiation, merging, and growth. The strong agreement between experimental and simulated results confirmed the method’s reliability, providing insights into localized corrosion mechanisms and long-term durability assessment of welded joints in engineering applications.