Effect of Single and Double Pulse MIG Welding Process Parameters on Microstructure and Properties of Aluminium Alloy

Abstract

Lightweight aluminium alloys are widely used in many industries due to their advantageous mechanical properties. As welding is a popular method for joining aluminium alloy sheets, it is important to understand how the welding process affects the alloy’s performance. Here, we investigated the influence of various operating parameters during pulsed metal inert gas (MIG) welding of thin aluminium alloy plates on the input energy and metallurgical microstructure of the weld. A series of welding tests were performed using surface welding of AA6061 aluminium alloy plates under conditions of a single strong-pulse, single weak-pulse, or double pulse. The morphology, metallurgical structure, and hardness of the welds produced using the different welding parameters were then examined. We observed that increasing the welding speed and the arc duration of low-energy pulses can reduce the heat input. Lower heat input is advantageous as it results in a higher cooling rate of the welding pool and a smaller average grain size of the weld structure. In addition, increasing the welding speed increased the hardness of the weld. Double pulsed MIG welding showed the best overall weld performance and is recommended for improving the quality of aluminium alloy bonding.