Tandem MIG welding of aluminium alloys

Abstract

Welding processes used in transport system manufacturing, such as the automotive industry, have in recent years seen a pronounced trend towards fabrication of lower-cost welded structures through efficiency enhancement focused on weld quality improvement. In this context, arc welding processes providing sufficient weld reinforcing ability, while allowing higher-speed welding are expected to emerge. In welding of aluminium alloys, MIG welding conferring superior economy and profitability holds out particularly high expectations, in future set to be the mainstream process for fabrication of welded structures. In MIG welding, however, straightforward adoption of higher welding speeds for efficiency enhancement purposes leads to loss of joint quality and weldpool turbulence due to increased current. Welding speeds therefore normally have an upper limit of around 1.5 m/min.¹ More recently, however, further welding speed increases have been sought through improvement of wire feed¹ and power supply² systems.