Exploring The Failure Mode And Mechanical Properties Of Spot Welded Dissimilar Joints For Austentic Stainless And Galvanized Steels

The spot welding of Austenitic Stainless Steel and Galvanized steel sheet is being widely used in manufacturing industry especially for automobile body building. The inter relationship between the individual spot welding parameters of dissimilar joints as well as the inter-relationship between the parameters, which determine the mechanical properties and failure mode are somehow not fully investigated in a systematic way, while the ‘one parameter at a time’ technique has widely been used. Hence, an attempt was carried out on dissimilar joints between AISI 304-2B Austenitic Stainless and JIS G3302 SGCC Galvanized Steel sheet, based on the Design of Experiment methodology to study the inter relationships between the spot weld parameters as well as their relationship with ultimate tensile stress and failure mode. This study was done by conducting ‘screening design’ in order to determine the key factors among the available parameters. The selected key factors were then used by applying response surface methodology to develop mathematical models for each response. The result showed that the weld current, weld time and squeeze time have positive effects on ultimate tensile stress and failure mode while electrode force, hold time and upslope have negative effects on both the responses.