Dissimilar Resistance Spot Welding of AISI 304 Austenitic Stainless Steel and AISI 1008 Low Carbon Steel: Correlation between Macro/Micro Structure and Mechanical Properties

This paper aims at investigating the correlation among macro/microstructure haracteristics and mechanical properties in dissimilar resistance spot welding of AISI 304 austenitic stainless steel (SS) and AISI 1008 low carbon steel (CS). Macro andmicrostructural investigation, microhardness and tensile-shear test were performed. Results showed that the fusion zone microstructure was ranged from Ferrite-Austenite-Martensite to full martensite depending on the melting/dilution ratio of basemetals which in turn was governed by welding current. Fusion zone size in CS side is the determining factor for mechanical performance of CS/SS dissimilar welds. Generally there is a direct relation between mechanical performance (peak load and failureenergy) and FZ size of low carbon steel side. Generally, increasing the welding current increases the peak load and energy absorption. However, on expulsion observed in welding current higher than 12 kA, the energy absorption was dramatically reduced.