EFFECT OF RESISTANCE SPOT WELDING PARAMETERS FOR STEEL SHEETS ON THE WELDING STRENGTH

Mechanical

Abstract

The resistance spot welding processes are widely used in the automobile, appliance and industries that use steel sheets, because of its low cost, high productivity, simple mechanism and applicability for automation. In this welding operation, two or more metal parts were joined together in a localized area by resistive heating and pressing force.
In this research, the effect of some welding parameters (voltage-current, and welding cycle time) on the resistance spot welding strength was investigated. Specimens made of mild steel sheet were spot welded and examined by using tensile test. The objective is to find out the optimum values of these parameters that give the best weldment strength which minimizes the frailer of the welded joint due to unsuitable welding parameters, and also to reduce the time and energy in using this process.
The results show that the welding parameters significantly affect the joint strength of the resistance spot welding. It shows that at low welding voltage-current, the welding joint strength increased by increasing welding cycle time, however at higher voltage-current, it increased by increasing welding cycle time to a specific values then started to decrease. It is obvious that voltage-current is more influential on welding joint strength than the welding cycle time. At (5 KVA) and (0.6 s) welding cycle time gave the best improvement in weldment strength for three sheet thicknesses (1, 1.5, and 2) mm of mild steel sheets