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A 2D axisymmetric electro-thermo-mechanical finite element (FE) model is developed to investigate the effect of current intensity, welding time, and electrode tip diameter on temperature distributions and nugget size in resistance spot welding (RSW) process of Inconel 625 superalloy sheets using ABAQUS commercial software package. The coupled electro-thermal analysis and uncoupled thermal-mechanical analysis are used for modeling process. In order to improve accuracy of simulation, material properties including physical, thermal, and mechanical properties have been considered to be temperature dependent. The thickness and diameter of computed weld nuggets are compared with experimental results and good agreement is observed. So, FE model developed in this paper provides prediction of quality and shape of the weld nuggets and temperature distributions with variation of each process parameter, suitably. Utilizing this FE model assists in adjusting RSW parameters, so that expensive experimental process can be avoided. The results show that increasing welding time and current intensity lead to an increase in the nugget size and electrode indentation, whereas increasing electrode tip diameter decreases nugget size and electrode indentation.

The effects of shunting current on metallurgical and mechanical behavior of resistance spot-welded (RSW) joints in AA2219 sheets are analysed experimentally via the investigation of mechanical and metallurgical properties, while numerical results predicted by the finite element method (FEM) are used to check the thermal aspects of the phenomenon and its effect on experimental results. Welding distance is chosen as the main variable for two consecutive nuggets. Predicted temperature distribution and cooling rates of FEM are verified by checking the nuggets and heat-affected zone (HAZ) dimensions, the SEM investigation of cracks, and performing a tensile-shear test. Experimental results have been in agreement with the predicted results, since HAZ development, the presence of cracks, interfacial failure, and poor mechanical strength of shunted nugget with shorter welding distance are all predicted in the form of temperature distribution and cooling rates of shunted nugget in finite element analysis (FEA). The temperature dependence of material properties and coupling between all aspects of the solution are respected in the FEA model while experimental tests are performed according to a three-factor design of experiment (DOE) to set the levels of factors based on their significance.