Estudo do efeito da geometria das extremidades do núcleo do eletroímã sobre a deflexão do arco de soldagem

Abstract

The application of a magnetic field in welding can be beneficially carried out, improving the processes. One of the objectives of using magnetic field in welding is to oscillate the welding arcs, replacing mechanic devices used for this purpose. This paper has the goal of searching for improvements in the oscillation of the welding arc by studying the tip geometries of a electromagnet core (magnetic deflection system of the arc) that imposes magnetic fields on the arcs. Some designs of tips with different geometries were designed, concerning both shape and number of edges. First of all, 2D and 3D visualization techniques of the field lines were developed e applied, using filings as identifier agents of the field lines. The objective was to verify if a field line visualization approach could predict the arc behavior when deflected by a magnetic. Second of all, an assembly to measure by a teslameter the field in several regions among the tips was employed. It was raised response surfaces to each tip, showing how the field lines distribution behaves. The results indicate that both visualization methodologies are consistent with each other and that they are capable of showing typical behaviors such as the field concentration in some regions and how the field directs itself when leaves the tips edges. However the field measurement technique proved to be more informative due to quantification of the field in the space, in contrast with an only indicative and didactic character achieved with the visualization methodologies. Finally, the generated magnetic fields from different tips were applied in actual arcs, initially in a stationary arc over an aluminum flat plane and, then, on an arc in movement, as much as in a flat plane steel as in a sheet overlap joint. The results showed that there is a good interconnection amongst distribution and intensity of visualized fields and measured with deflection and displacement of the arc and between the deflection and displacement of the arc with the geometry of the formed string. They also showed that the study of tip geometry can increase the welding efficiency such as when you want to weld joints or deposit overlays.