Evaluation of toptig technology applied to robotic orbital welding of 304L pipes.

In recent years, a new variant of the GTAW process, commercially named TopTIG, has attracted interest in the industrial sector due to the possibility of increasing productivity and facilitating automated operation. In this technology, the main component is a special welding torch that allows the insertion of a wire tangentially, in a region closer to the tungsten electrode when compared to traditional torches in the GTAW process. In addition, the wire guide is incorporated into the nozzle, making the torch more compact, facilitating operation using an anthropomorphic robot. In a context where automation is desirable to increase productivity even in the most complex manufacturing processes, the use of this new variant as an alternative to facilitate the development of pipeline orbital welding procedures was investigated. The research was conducted to develop procedures for the root and fill passes using 304L stainless steel tubes, with a diameter of 305 mm and thickness of 12.7 mm. In the root pass welding the Keyhole technique of welding was used. The results showed that this technology allows an increase in welding speed and melt rate of wire up to twice in the welding of the root pass compared to other studies found in the literature which use GTAW techniques with larger insertion angles. Therefore, wire feed speeds of approximately 4 m min−1 and welding speeds of up to 0.5 m min−1 were used. The study highlighted the challenges inherent to the robotic application of the GTAW process for orbital welding, especially in relation to the root pass. However, for the envisaged field application of the technology, further robustness oriented welding procedure development must be undertaken, since the process is still sensitive to geometric variations typically found in joint connecting pipes. • Robotic orbital welding with GTAW is possible through a thorough study of welding parameters. • The welding of the root pass with the robotic GTAW process is extremely sensitive to geometric variations of the joint. • Welding of the root pass is possible without changing parameters after obtaining a robust parameterization. [ABSTRACT FROM AUTHOR]