A Methodology for the Counting Distribution Analysis of the Reignition Voltage Peaks for Stability Evaluation of Short Circuit GMAW Process

Abstract

The stability of the welding arc has been studied through statistical analysis, obtained mainly from the voltage and current signals. Histograms and statistics of open arc time and short circuit time are important means of evaluating the welding processes stability. However, studies related to electric arc reignition voltage peaks are still poorly explored. Thus, this work presents a methodology for the evaluation of the arc re-ignition voltage peaks of the Short-Circuit Gas Metal Arc Welding (GMAW-SC) process and its relation with the regularity of the welding voltage signals. Weld beads were deposited on flat plate, varying the gas, in order to produce different distributions of re-ignition peaks. Pearson's chi-square test was applied to evaluate the distribution of peak voltage frequencies and compared with the hypothetical distribution. A standard weld bead was compared to its replication and tested for equal distributions. The results showed that exist equal voltage peaks distributions between weld beads, being dependent on the welding parameters. It was concluded that the proposed methodology is able to the statistical study of the distribution of welding arc re-ignition peaks. It was also demonstrated that the arc stability in GMAW-SC can be evaluated by the analysis of the voltage peaks distribution.

Key-words:
Welding Processes; Stability; Short-circuit GMAW process; Arc re-ignition