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Abstract
The use of pulsed current for MIG welding of aluminium, despite being one of the most recommended technologies, due to its better results, presents difficulties at the start of the process, principally in regard to arc initiation. With the aim of developing a more suitable process of arc initiation, two new techniques were studied: the first based on the imposition of a high current, combined with an interruption to wire advance, and the second using the application of a low current, linked to wire return, which necessitated perfecting a wire feeder. The first technique, despite ensuring arc ignition, resulted in two forms of initiation condition by the geometry of the wire point. One of them is explosive with ignition close to the middle length of the electrode wire, and the other smooth with ignition close to the point of contact between the electrode wire and the base metal. The second technique, regardless of the geometry of the wire point, promoted smooth initiation, with low heat support and arc ignition always close to the point of contact between the electrode wire and the base metal, and was considered to be more suitable than the first.