In industrial settings, it is customary to employ at least a three-passes welding for 9.525 mm-thick welded samples, which results in increased angular distortion and longitudinal/transversal deformation. This study outlines the optimized welding parameters for a butt-welded joint V groove with a 60-degree bevel angle and a 2.5 mm root face, utilizing a single pass, on a 9.525 mm thick sample. The present investigation involved the development of a 3D computational model to examine the thermal characteristics and distortion distribution during the process of gas metal arc welding of the aluminium alloy 6061-T6. The present paper employed the Taguchi methodology to compute the thermal behaviour technique using orthogonal arrays, a well-established Design of Experiments (DOE) approach for finite element analysis (FEA). Additionally, an artificial neural network (ANN) model was employed to forecast distortion and stress. The study produced 3D surface graphs and contour plots to clarify the correlation between welding parameters, stress, and distortion. Following the determination of optimized parameters through finite element analysis (FEA), experimental tests were conducted to compare and validate the FEA outcomes. The present investigation has employed welding parameters, namely arc voltage (v), arc travel speed (mm/s), current (A), gun angle (degree), distance between the nozzle and weld (mm), and root gap (mm).