An improved model for cold metal transfer welding of aluminium alloys

An improved model is proposed for automated cold metal transfer (CMT) welding based on a time-dependent double-ellipsoidal volumetric heat flux distribution. Equations are evaluated numerically within COMSOL Multiphysics for CMT welding of a 3-mm-thick AA5754 AlâMg alloy plate. The simulation calculates transient and steady-state temperature distributions within the weld seam and heat-affected zone (HAZ). Validation of the model is achieved by comparing simulated temperatures with measured values from thermocouples in the HAZ during welding experiments, as well as through comparison of the calculated fusion zone and microscope images of the weld seam. Under steady-state conditions, large differences between the peak and average calculated temperatures in the weld pool highlight the underlying phenomenon responsible for improvements in weld quality for thin sheets with CMT compared to conventional joining processes. The developed simulation provides opportunities for process optimisation and sensitivity analysis in many applications