CONSIDERATIONS ON ARC INTERRUPTIONS IN PULSED GMAW

Ruham Pablo Reis¹; Américo Scotti¹

¹ Universidade Federal de Uberlândia

Resumo

Problems of arc interruption (transitory extinction) and, therefore, oscillation in the amount of energy and molten wire delivered to the plate, have been noticed during pulsed tandem GMAW (UEYAMA et al., 2005). Although it is not so clear, this phenomenon seems to be related to the magnetic field generated by the arcs. In order to clarify this troublesome, this work tries to mimic the situation found in tandem GMAW (magnetic field induced by one arc acting on the other arc). Pulses of external magnetic fields were applied to GTAW arcs in constant current mode to verify their resistance to extinction as a function of the current level. In order to generate the external magnetic fields, an electromagnet was devised and driven by a variable DC power source. Highspeed filming was used as an additional tool to understand the extinction mechanism.

Palavras-chave: pulsed GMAW