The AC MIG/MAG process presents remarkable application potential, since it allows join the characteristics of the conventional MIG/MAG process (direct current, electrode positive) with the ones obtained when negative current is applied in MIG/MAG welding. However, the current wave shape (alternate, pulsed in positive and constant in negative polarities) demands a criterions selection of its innumerous setting parameters, fact that limits the development and application of this process version. The objective of this work was to propose and assess a methodology able to estimate the setting parameters of the CA MIG/MAG welding process, in such a way to result in welds with arc length stability and adequate bead geometry. A step-a-step description of the input parameter definitions and of the way to experimentally obtain some parameter values needed to estimate other setting parameters. The estimation equations are presented and discussed. A demonstration of the methodology application is carried out, with validation through actual welds.
MIG; Alternate Current; negative polarity; parameter selection
