Optimization of resistance spot welding process parameter on quenched steel by Taguchi methods

Abstract

The optimization of resistance spot welding process parameter on quenched mild steel by Taguchi method is the main focuses in this research. Firstly, the parameter that being controlled are welding current, welding time and hold time and each of the factor that has been listed having three level for each factor. Secondly, the mild steel need to be heat treated by using quenching technique at 900ºC for 2 hours soaking time which is to improve the strength and ductility. After that, orthgonal array (OA) were made by using the data parameters and forming L9 3*3 pattern before handling the RSW process. Then, visual inspection was held to identify the behaviour of weld nugget which is the nugget size of fusion zone measured using vernier calipers and the failure mode that occur during the process is held. From the visual inspection, it can be observed that when the welding current increase the nugget size diameter at the fusion zone also increase significantly. The mechanical properties of the spot welded mild steel were determined by using tensile shear strength test and Vickers microhardness test. Results were used to simulate for statistical S/N ratio and ANOVA calculation to find the most effective parameter. Results shows that the most contribution factor and an optimum parameter is achived by using sample mild steel with a thickness of 1.5 mm.