Geometrical Characteristics of Pulsed Current Positional GMA Weld.

Abstract

Vertical up positional welding of structural steel plate was performed by pulsed current GMAW process employing comparatively high mean currents of 100 and 130 A, resulting an enhanced deposition rate. The use of welding current of conventional continuous current GMAW at similar order to those of the mean currents of the pulsed current GMAW process is found unsuitable in present conditions of welding. However, the geometrical characteristics of the weld are found to be largely governed by the pulse parameter of the GMAW process and they are well correlated to a factor φ defined as a summarized influence of pulse parameters such as peak current, base current, pulse off time and pulse frequency. The increase in φ at a lower mean current is found favourable to obtain acceptable weld geometry, especially with respect to the form factor and toe angle of the top reinforcement of the weld.