Process Parameters Effect of Resistance Spot Welding on Weld Quality

Abstract

Resistance Spot Welding is a process of joining the sheet metal parts. In this study spot welding machine is used to weld the pads on a pan of the fuel tank. Material used in fuel tank’s pan and pad is Cold Reduced Low Carbon Steel Sheet. The thickness for pad is 1.50 mm and for pan is 0.80 mm (Galvanized). The diameter of electrode used for spot welding is 5mm. There is a rejection of fuel tank due to low weld tensile strength. So, DMAIC (Define, Measure, Analyse, Improve & Control) method and Taguchi Method is used for reduction in rejection level. Experiment is carried out on Resistance Spot Welding machine. The highly effective parameters as welding current and weld cycle time with their different levels are used. These parameters are affecting the quality of resistance spot welding in terms of tensile strength, nugget size and internal defect. Each parameter has its effect on output quality parameter. The purpose of this study is to find out the effect of two control parameters like welding current and weld cycle time of resistance spot welding machine on tensile strength, nugget size and internal defect of the spot welding as a weld quality. Ultrasonic Flaw Detection Test as a Non-Destructive test and Tensile Test as a Destructive test is used. Optimization of welding current and cycle time by using software is used for reduction in rejection level.