GEOMETRICAL CHARACTERISTICS OF PULSED CURRENT POSITIONAL GMA WELD

Vertical up positional welding of structural steel plate was performed by pulsed current GMAW process employing comparatively high mean curr ents of 1 00 and 1 30 A, resulting an enhanced deposition rate. The us e of welding current of conventional continuous current GMAW at simila r order to those of the mean currents of the pulsed current GMAW proce ss is found unsuitable in present conditions of welding. However, the geometrical characteristics of the weld are found to be largely govern ed by the pulse parameter of the GMAW process and they are well correl ated to a factor phi defined as a summarized influence of pulse parame ters such as peak current, base current, pulse off time and pulse freq uency. The increase in phi at a lower mean current is found favourable to obtain acceptable weld geometry, especially with respect to the fo rm factor and toe angle of the top reinforcement of the weld.