AN EXPERIMENTAL-STUDY OF RESISTANCE SPOT-WELDING IN 1 MM THICK SHEET OF LOW-CARBON STEEL

Investigations on the influence of welding parameters such as welding current, electrode force and weld time in resistance spot welding proc esses have been carried out with the help of a specially developed sim ulator. The effect of these parameters on dynamic contact resistance a s well as on the quality of weld joint in terms of weld joint strength , nugget diameter, etc., was studied and conclusions have been made. E xperiments have been carried out on 1 mm thick St1203 (DIN 1623) type of steel. Experimental observations were analysed statistically to obt ain an empirical relationship between weld strength and the welding pr ocess parameters and subsequently a polynomial relation of second orde r has been fitted with a satisfactory degree of reliability. From thes e results welding lobes were also drawn which will provide information on different conditions needed for specified weld strength and also e nsure a minimum guaranteed strength at those combinations. The possibi lity of using dynamic contact resistance as a means of monitoring the quality of spot welds has been explored and certain important observat ions are reported.