Analytical estimation of thermomechanical distortion and interface layer thickness for gas metal arc lap joining of dissimilar sheets

The thermomechanical distortion and the evolution of an interface layer with intermetallic phases are the two critical challenges for gas metal arc overlap joining of multimaterial sheets. Two novel analytical methods are proposed following mechanistic principles to estimate the thermomechanical distortion and the interface layer thickness. The analytically estimated results are tested rigorously with the corresponding experimentally measured results for gas metal arc joining of aluminium and steel sheets for different process conditions. Both the thermomechanical distortion and the interface layer thickness are influenced predominantly by the wire feed rate and the resulting heat input. The interface layer thickness and the thermal distortion are found to be the minimum for a heat input of 42.4 J/mm corresponding to the lowest wire feed rate of 4 m/min and the highest travel speed of 10 mm/s. The proposed analytical methods can serve as practical easy-to-use design tools for appropriate selection of process variables in gas metal arc overlapped joining of dissimilar sheets to mitigate the joint distortions and restrict excessive growth of the interface layer.