Experimental and numerical analysis on electrical resistance spot welded dissimilar stainless steel alloys

Abstract

Resistance Spot Welding process (RSW) is a famous joining technique used in the manufacturing of car, buses, railway body assemblies and repair work etc. due to its high processing speed. Thousands of spot welds are required to complete a body of automobiles. Accordingly, automobile industries are showing interest in joining stainless steel sheets using RSW process. Among the various varieties of stainless steel, the AISI 316L stainless steel is widely used by fabricators due to its excellent toughness, ductility, corrosion resistance and weldability. Duplex stainless steel (DSS) which consists of ferrite (and#945;) and austenite (and#948;) dual-phase microstructure exhibits a perfect combination of superior mechanical properties and excellent corrosion resistance. Joining of austenitic stainless steel and duplex stainless steel has become a significant competitor to join similar grades of stainless steel in food and beverage manufacturing and processing industries for making equipment like containers, vats, ovens, etc. The selected combination of dissimilar metals for resistance spot welding is satisfactory for service conditions such a high thermal cycles and corrosive environments. AISI 316L stainless steel and 2205 Duplex stainless steel of 2 mm thick are taken as the candidate materials for the present study. A superior weld quality is produced by adjusting or setting suitable welding process parameters. This can be performed by utilizing some optimization techniques. In this present work, Taguchi optimization technique is employed for optimizing the process parameters. The analysis is executed by considering LBH (Larger-the-Better) quality characteristics since the response i.e. tensile-shear fracture load (an inherent property of the weld metal) is predicted to be as high as possible. The ANOVA results show that the most effective and dominant control factor for achieving high tensile shear bearing load capacity is welding current, then comes the heating cycles and the least effective response factor is electrode tip diamete newline