Study On Welding Process Of 5356 Aluminum Alloy Tri-arc DE Welding

A new method of high efficiency additive manufacturing for aluminum alloy is put forward from an innovative angle.There are not only two arcs between wires and workpiece,but also the third arc between two wires.The introduction of the new arc makes it possible to adjust the ration of current through the wire and the workpiece,so that heat input to the workpiece can be controlled,which makes this new welding method has advantage of high deposition efficiency and low heat input.First of all,using the high-speed camera,shooting arc shape and droplet,with the wire feeding speed increasing,the wire extension becomes larger,the arc length decreases,and the arc is compressed,the trend of the arc energy become centralized at first and decentralized at last;when elevate the voltage,the length of the arc become longer,at the same time,the arc capacity become lager.The droplet transfer form is short circuiting transition firstly,then with the M current increasing,it is a mixed transition form of short circuiting transition and jet transition.Secondly,based on experiments,the influences of welding parameters on the cathode cleaning effect are studied.Both the width of the cleaning zone and molten pool are taken into account during the study of the influence of the welding parameters on the cathode cleaning effect.With the increasing of wire feed speed,the cleaning width becomes much bigger;with the increasing of M current,cleaning width becomes smaller,so the cleaning effect becomes worse;the distance between the nozzle and workpiece should be set from 10 mm to 15 mm in order to obtain the best cleaning effect;using high pure argon gas protection can achieve better cleaning effect than that of ordinary argon.Thirdly,the influence of welding parameters on the weld appearance was studied.With the increasing of wire feed speed,deposition rate is almost linear increase,the weld coefficient firstly decreasing and then increasing;in the same welding parameters,to elevate M current will reduce the workpiece heat input,so as to reduce the welding stress and deformation.Finally,the mechanical properties and porosity of 5356 aluminum alloy welded joints were tested and analyzed.The experimental results show that when the welding voltage is 25 V,the wire feeding speed is 6.0m/min,and the M current is 36 A,the welding joint can obtain the best performance.