Investigation of welding parameters effects on residual stresses of resistance spot welding of AZ31 alloy

Due to the growing utilize of lightweight materials and the wide use of resistance spot welding in the several industries, in this study was investigated the effect of welding parameters on residual stresses of resistance spot welding of AZ31 magnesium alloy. Resistance spot welding is a complicated multi-regime phenomenon which simulated by a developed electro-thermo-mechanical coupled finite element model. The importance of the parameters interactions was determined by using design of experiment method (DOE). The FE model used to predict temperature changes, nugget growth, and the residual stresses distribution. For validation, the results of the simulation were compared with experimental data, based on the nugget diameter at the direct current (DC) and alternating current (AC) conditions. The results showed that by increasing current and welding time the residual stresses are reduced. Increasing electrode force causes to increase residual stress but increasing holding time causes to create a peak in the amount of residual stresses. Also, evaluation of current sources revealed, in the same conditions, using direct current creates less residual stress than alternating current.