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The objective of this work is to evaluate the behaviour of short-circuit frequency and duration time and electrical conductivity during arc re-ignition in the shielded metal arc welding process with alternating current and E6013 electrodes. The non-parametric statistical analysis guarantees robust processing of the data, reducing the influence of atypical values and errors derived from the use of approximations to well-known continuous distributions. The median and the median absolute deviation (MAD) with respect to the median of the data are the localization and dispersion estimators used, respectively. The electrode set at 160 A shows a better stability in metal transference, given for the lowest value of MAD for the short-circuit period (39.36 ms), and the MAD of the short-circuit duration (1.43 ms), according to the presence of a major electrical conductivity during the arc re-ignition (1766.17 × 10− 3 S s− 1).

The objective of the present work is to evaluate the effectiveness of a self-feed device for coated electrodes. This device is able to eliminate disturbances from manual operation or the use of automatic control systems during the study of coated electrode behaviour. The conjugation of different methods such as short-circuit time statistical analysis and metallographic analysis (penetration, heat-affected zone, shape and mean distance between successive solidification fronts) together with the analysis of the electric arc and electrode melting parameters allows us to obtain relationships between arc behaviour, mass transfer processes and bead appearance. This permits the extraction of criteria to describe process stability and the behaviour of the feed device employed. An appropriate statistical methodology was obtained to process the ‘duration of the short-circuit’ parameter through an appropriate adjustment of empirical distributions to a log-normal model. The self-feed device for coated electrode weldi...