Adaptation of the plasma process with automatic wire feeding for recovery of surfaces by automated welding

摘要

Damaged surfaces are normally recovered by means of processes of welding; they normally have complex geometries and are located in positions that are unfavourable for welding. Automated welding is the natural alternative as it presents advantages when compared with the manual process, such as reductions in the time and total cost of the recovery, better control of the geometry of the recovered surface, better uniformity and welding quality. Automated welding using the plasma process with automatic wire feed, although it provides excellent geometric and surface quality for the deposits, a significant reduction in welding defects and an absence of spatter, is very sensitive to variations in the torch-piece distance and to changes of welding position. In this context, the present work deals with an analysis of the changes made to the position of the wire in relation to the electric arc and the weld bead, to the orientation of the torch in relation to the surface to be welded and to the welding parameters that make the plasma welding process more robust due to geometric alterations to the surface to be welded. The practical results achieved in the most critical situations, from the point of view of welding damaged surfaces, are presented with the objective of validating the changes proposed for the fed plasma process.