The effect of welding atmosphere on the pitting corrosion of AISI 304L resistance spot welds

Austenitic stainless steel has excellent properties with respect to general corrosion resistance, while it is sensitive to localized corrosive attacks, such as pitting and crevice corrosion in humid and chloride-containing atmospheres. This pitting corrosion susceptibility increases when it is exposed to conditions like resistance spot welding (RSW) process. The current research deals with the effect of RSW shielding gas atmosphere on the pitting corrosion behavior of AISI 304L austenitic stainless steel weld joints. Optical and SEM investigations show several types of pit sizes and morphologies depending on heat input and shielding gas. Cyclic potentiodynamic polarization (CPP) of welded nuggets shows that argon gas is more effective in the improvement of pitting corrosion resistance at low heat input, while nitrogen demonstrates better corrosion resistance at high heat input.