Application of Fast Weaving to CO_2 Arc Welding (Report I) : On Bead Appearance and Spattering Loss(Welding Physics, Processes & Instruments)

概要

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An application of the weaving to bead-on-plate CO_2 arc welding is studied using a conventional weaving device which has the welding torch oscillate transversely to the welding direction like the pendulum motion in the range of 0 to 30Hz in frequency and 0 to 8mm in amplitude. Bead appearance and spattering loss are examined under various oscillation conditions and it is shown that there is optimum condition under which the smoothness of bead is improved and the spattering loss is reduced to 1/3〜1/4 as compared with that in non weaving case. Most suitable conditions with respect to the bead appearance and spattering loss are in the region of oscillation of 5 to 15Hz in frequency and 3 to 7mm in amplitude in the case of middle current CO_2 arc welding. The phenomena and the movement of molten metal during welding are observed using a high speed movie and the discussions concerning the mechanism for the reduction of spattering loss under the proper oscillating condition are described. The burried arc and stable movement in the pool is the reason to the improvement of the bead appearance and the reduction of spattering loss. The change in the shape of fusion zone is discussed with an approximated calculation based on Rosenthal's heat conduction theory.