Combined Effect of Resistance Spot Welding and Post-Welding Sensitization on the Pitting Corrosion Behavior of AISI 304 Stainless Steel

This work studies the combined effect of resistance spot welding and post-welding sensitization on the pitting corrosion behavior of AISI 304 (UNS S30400) by using cyclic potentiodynamic polarization tests. The combined effect of welding and post-welding sensitization give rise to worse pit nucleation resistances and better repassivation capacities than those of the state without prior welding. This behavior is caused by the weld metal zone, a cast dendritic microstructure with δ-ferrite in interdendritic regions, whose microstructural regeneration kinetics is faster than that of HAZ and that of the parent metal and where the chromium-rich phases are more homogeneously distributed than in the parent metal.