High-Frequency Pulse on Arc Characteristics and Weld Formation in Double-Wire Median-Pulsed Gas Metal Arc Welding of Aluminum Alloys

Abstract

Abstract. A hybrid welding process that combines high-frequency pulses (HFP) with double-wire median-pulsed gas metal arc welding (GMAW) was proposed to retain the welding efficiency of double-wire welding while simultaneously enhancing weld quality. The effects of HFP amplitude on arc characteristics and weld formation in double-wire median-pulsed GMAW were systematically investigated. The arc electrical load characteristics and arc profile features under different HFP amplitudes were analyzed using voltage–current (U–I) characteristic curves and high-speed images, respectively. The experimental results demonstrated that the arc load remained stable throughout the welding process, and the double arcs consistently exhibited an overall V-shaped morphology under different HFP amplitudes. However, as the HFP amplitude increased, the proportion of the arc core region gradually increased, and the average current density exhibited an increasing trend. Based on the double arc pressure equation, HFP enhanced the axial arc pressure. Furthermore, the results showed that HFP exerted a significant influence on weld formation and porosity. With increasing HFP amplitude, the intensified longitudinal vibration and convergent flow within the weld pool accelerated internal heat transfer, thereby increasing weld penetration while reducing weld width. In addition, the enhanced fluid flow facilitated pore escape from the weld pool, resulting in reduced porosity.