AN EXPERIMENTAL STUDY ON THE SHUNTING EFFECT IN RESISTANCE SPOT WELDING OF MILD STEEL by Ratanjot Singh Lamba
Abstract
Resistance Spot Welding is the most widely used welding technique for joining the sheet metal parts. This research work is mainly focused on the shunting effect which is encountered frequently in the spot weld operations. In many applications, several spot welds are made closer to each other. The second spot made after the first spot may encounter a reduction in its nugget diameter due to the shunt effect. In this present study, the effect of weld distance, weld current and weld time have been studied on the shunted nugget diameter and micro hardness of the weld joint. Optimization of the weld parameters for the second spot weld has also been done using Taguchi method for obtaining the maximum breaking strength of the welded joint. The results showed that a smaller weld spacing promotes more shunting whereas increasing the weld current for the shunted spot eliminates shunting. The weld current had the maximum contribution to reduce the shunting followed by weld distance and weld time. Optimization results showed that increasing the weld current is better option as compared to increasing the weld distance to reduce shunting as increase in welding distance adversely affects the breaking strength of the weld joint.
