TIG welding process with dynamic feeding: a characterization approach

Wire forward and backward oscillation in automatic feeding tungsten inert gas (TIG) process have been pointed as a simple technique to achieve high productivity levels and process stability for a wider operation range, compared to the conventional version. However, in this case, physical aspects related to the involved phenomena are still not fully understood. Based on that, the present paper addresses a characterization analysis of low frequency dynamic wire feeding process, in order to yield some contribution to the knowledge gain of these phenomena. Both conventional automatic feeding and autogenous process were taken as a reference. The study covers system description as well as metal transfer modes, welding pool temperature gradient, and respective weld geometry. Bead on plate welding was performed and monitored with high-speed and thermographic cameras. Dynamic oscillation showed good stability and proved to be more flexible among other versions, as feeding speed and power do not need to be correlated. In order to enable proper wire dynamic movement monitoring, a special motion measuring system was developed.