This study analyzed the average temperature value of the metallic droplets and weldpool of the Pulsed GMAW welding process using 309L-Si electrode as the addition metal. The study was based on the formulation and evaluation of pulsed waves, starting from the equation of energy constant (or detachment constant), and waveforms from two commercial welding sources, that were evaluated and reproduced. The technique of filming by high speed infrared radiation was used for evaluation. The results point to a higher droplet temperature for a lower intensity of pulse current, due to longer dwell time at this level, and also revealing that a longer time in the base phase may be responsible for a further heating of the fusion pool.

Abstract: Recent profusion of advanced GMAW process variants impairs understanding of the nature of each one, with the arc rotation technique among them. This paper’s objective is investigating influences of wire-electrode rotation over metal transfer mode and melting rate. A bead on plate experimental matrix was performed and electrical signals acquired in synchronicity with high speed videography. Impacts of electrode rotation were observed on welding voltage and current, whereby rotation speed exerts marked influence. Droplet short-circuiting frequency was affected, culminating in free-flight transfer mode for higher rotation speeds. Increase of melting rate was observed for lower electrical power, indicating efficiency enhancement of the process. Moreover, arc rotation proved to expand controllability of the thermal development of the workpiece. Results are supported by videothermography.