Research On Metal Transfer And Welding Process Of Triple-wire P-GMAW Of Aluminum Alloy

In order to solve the undercut problem of single-wire or twin-wire P-MIG welding under high welding speed,triple-wire P-GMAW is proposed by scholars.However,there are still some problems with triple-wire P-GMAW,such as arc interference and poor welding stability.At present,domestic and foreign research has focussed more on equipment and efficiency,and there is relatively less research on welding arc behavior and the droplet transition.Arc characteristic and the process of droplet transition of aluminum alloy were analyzed.In addition,a series of experiments were designed to explore the effect of different welding parameters on weld formation and welding stability.The results obtained are as follows:The transfer process of aluminum alloy of triple-wire P-GMAW mainly contains: pulsed short-circuiting transfer,pulsed meso-spray transfer,and pulsed spray transfer.The process of droplet transfer may be inconsistent between leading wire and trailing wires in pulse short-circuiting transition,while for pulsed meso-spray transfer,a mixed transition process of pulsed short-circuiting transfer,pulsed meso-spray transfer,and pulsed spray transfer usually exits.But for pulsed spray transfer,arc deviation and arc interruption can be obvious.Moreover,the current and voltage also have an important influence on the droplet transfer mode.Triple-wire P-GMAW experiments were carried out and the effect of welding parameters on weld formation and welding stability were studied to obtain the proper welding parameters,which included electrode arrangement,welding currents /voltages,welding speed,contact tip-to-base metal distance.The results shows the contact tip-to-base metal distance plays an important role in the weld quality,and the stability of trailing arcs are more easily affected by the change of the distance from the contact tip to the workpiece.The influence of welding speed on the stability of leading arc and trailing arc is different,with the increase of welding speed,the stability of leading arc decrease,while the stability of trailing arcs increase.The current and voltage greatly influent on the degree of arc interference,when the leading arc current is slightly larger than the trailing arc and the voltage is slightly smaller than the trailing arc,the welding process is stable.