An Experimental Study of Resistance Spot Welding in 1 mm Thick Sheet of Low Carbon Steel

Abstract

Investigations on the influence of welding parameters such as welding current, electrode force and weld time in resistance spot welding processes have been carried out with the help of a specially developed simulator. The effect of these parameters on dynamic contact resistance as well as on the quality of weld joint in terms of weld joint strength, nugget diameter, etc., was studied and conclusions have been made. Experiments have been carried out on 1 mm thick St1203 (DIN 1623) type of steel. Experimental observations were analysed statistically to obtain an empirical relationship between weld strength and the welding process parameters and subsequently a polynomial relation of second order has been fitted with a satisfactory degree of reliability. From these results welding lobes were also drawn which will provide information on different conditions needed for specified weld strength and also ensure a minimum guaranteed strength at those combinations. The possibility of using dynamic contact resistance as a means of monitoring the quality of spot welds has been explored and certain important observations are reported.