MIG welding of aluminium alloy using digital inverter type pulse welding machine (Report 2)

―Study of parameters for relevant welding performance―

Abstract

The digital inverter control type pulse (DP) welding machine is currently used for MIG welding. In comparison with conventional equipment, the DP welding machine is superior in workability and weldability. However, welders have not fully identifed its relevant welding parameters. In our previous paper, the butt joints in the flat position were selected and relevant welding parameters were examined.In this study, the butt joints in the vertical and horizontal positions are selected and relevant welding parameters are examined. The thicknesses of aluminum alloy (A5083P-O) used for parent plate are 3, 8, and 20 mm, and the diameter of the wire (A5183-WY) used is 1.2 mm. An X-ray radiographic test and a bending test are carried out on the specimens produced with relevant parameters. No imperfections are detected by either test.The followings are provided as examples of relevant welding parameters.(Ⅰ)Vertical position (1) for 3 mm thick butt joint: welding current 60 A, welding voltage 17.7 V, welding speed 3 mm/sec, 1 layer-1 pass: (2) for 8 mm thick butt joint: welding current 150-160 A, welding voltage 22.9-23.4 V, welding speed 3 mm/sec, 2 layers-2 passes: (3) for 20 mm thick butt joint: welding current 180-200 A, welding voltage 24.5-25.6 V, welding speed 3 mm/sec, 5 layers-7 passes.(Ⅱ)Horizontal position (1) for 3 mm thick butt joint: welding current 60 A, welding voltage 16.6 V, welding speed 3mm/sec, 1 layer-1 pass:(2) for 8 mm thick butt joint: welding current 150 A, welding voltage 21.5 V, welding speed 3-4mm/sec, 2 layers-3 passes: (3) for 20 mm thick butt joint: welding current 150-200 A, welding voltage 21.5-24.0 V, welding speed 2.6-4.3 mm/sec, 3 layers-8 passes.(Ⅲ)The control facility of the DP welding machine is progressing extremely compared with the conventional machines. Consequently, we can obtain the welding result permitted by use of the unit parameters installed except for the special case. In use of the DP welding machine, the determination of the average welding current as which unit parameters are determined is primary importance. The method of manipulation of a torch and the selection of welding speed are important too.