Research On Arc Behavior And Characteristics Of Metal Transfer In Double-pulse MIG Welding

The double pulse MIG welding for aluminum alloys is a new welding method in recent years.The research is focused on the welding equipment and organizational performance and so on at present in China,while which is also relatively less in the research of welding arc and the metal transfer.In this paper,the high-speed imaging system and electrical signal collecting system will be used to collect the image and electrical signal of the arc and metal transfer in double pulsed MIG welding for 6061 aluminum alloy plate with the thickness of 3mm.The information collected will be used to analyze the arc behavior and the process of the metal transfer.The results obtained are as follows:The better stability is performed in double pulsed MIG welding process in contrast with the pulsed MIG welding process.In the pulsed MIG welding process,the arc performs differently during the peak phase and base phase,and during the peak phase the arc goes stably,while uncertain during the base phase.In the double MIG welding process,the arc performs stably during the strong pulse phase and weak phase.Compared the pulsed and the double pulsed welding arc,it is found that the volume of arc in double pulsed welding is large than that in pulsed welding during the peak phase,while during the base phase the arc of double pulsed welding performs higher brightness than that in pulsed welding process.For the welding appearance,the both exhibits from narrow to wide.But for the pulsed MIG,the appearance is not good,while that of the double pulsed MIG is better,whose welding seam is bright and beautiful.The transfer process of aluminum double pulsed MIG mainly contains: short circuit transfer,projected transfer,sub-shot stream transfer.The short circuit transfer is not stable,while for the projected transfer,a drop of a pulse and two or three drops of a pulse exits in some welding processes.During the process,both the welding current and wire feed speed will affect the process of droplet transfer.Another study is found that the droplet transfer have a certain relationship with the arc shape,for example,the shape of the arc with the projected transfer is bell-shaped.But in the projected transfer process,the arc shape performs cluster not bell-shaped at the early arrival of the peak arc.Statistical principle is used to analyze the stability between the pulsed and double pulsed MIG welding process,and it is found that the latter performs better.Also the voltage distribution histogram is proposed to analyze the stability of the arc,which is simple and intuitive.