Representatividade dos valores de correntes média e eficaz na formação do cordão em soldagem a arco

Abstract

There are several variables that characterize arc welding bead formation. However, there is not consistent information discussed and justified in the current literature about the representation of the current (average and effective) for the characterization of the weld bead formation. Based on this fact, a question about the proper way to express current, either as average or as effective, to represent its effect on the formation of a weld bead still persists. In order to promote this discussion, automated welding trials were performed with the TIG process, by using constant and pulsed currents, keeping the same value of average current, yet with growing effective current values (achieved by pulse and base parametrization of the pulsed cycle). The relationship between the two forms of current representation and the geometrical aspect of the resultant beads, as penetration, width and molten area, were analyzed. In addition, the same relationship was searched for with the same parameters towards the absorbed heat measured by cryogenic calorimeter technique. All geometric parameters and the absorbed energies increased with the mean current levels expressed by both average and effective representation. These results showed that both representations of current (average and effective) are necessary to represent more consistently the influence of the current on the bead formation in arc welding.