Avaliação da influência da distância entre o bico de contato e a peça na taxa de fusão no processo de soldagem MIG/MAG.

Abstract

The main objective of this work was to evaluate the influence of the contact tip to workpiece distance (CTWD) on the melting rate of the electrode wire in the MIG/MAG welding process. With this objective, the impact of the CTWD variation on the fusion rate for three electrode wires of different diameters was compared. In order to make such a comparison, the idea was to keep the welding parameters constant (the arc voltage and the welding current) when carrying out the tests for each wire diameter, varying only the CTWD, so that it was possible to observe its impact on the melting rate of each wire without interference from possible variations of other welding parameters. The results showed a quite significant increase in the melting rate for each millimetre added to the CTWD. In addition, it was observed that this behaviour, an increase in the wire fusion rate with an increase in DBCP, changes according to the diameter of the electrode wire, due to the influence of the Joule effect on the wire varies according to its diameter. A maximum rate of 3.33% of increase in the wire melting rate per millimetre added to the CTWD was obtained for the electrode wire with a nominal diameter of 0.9 mm, the thinnest of all tested wires. As a result, a higher melting rate (greater efficiency) is achieved using the same amount of energy.