Effect of Surface Morphology on Galvanic Corrosion Resistance at Welds after De-rusting

To study the effect of surface morphology on the corrosion resistance of weld after de-rusting, corrosion de-rusting tests, metallographic tests, and electrochemical tests were carried out. The relationship between surface morphology after de-rusting and the corrosion resistance at the weld was discussed. Based on the microstructure of the welding surface obtained by metallographic testing, a finite element model of weld corrosion was established to study the effect of the welding surface morphology on the galvanic corrosion process after de-rusting. The results show that the welding surface roughness significantly affects its corrosion resistance. The rougher the welding surface, the smaller the potential difference between it and the surrounding base metal, enhancing its corrosion resistance. Galvanic corrosion at the weld can make the surrounding base metal more susceptible to corrosion. However, this effect diminishes as the welding surface roughness increases. Consequently, during welding de-rusting, a moderate rise in welding surface roughness can effectively reduce its corrosive impact on the surrounding base metal.