鋼の大電流 MIG 溶接法におけるアーク現象と溶滴移行形態

概要

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This paper describes the arc physics which forms the basis of large current MIG arc welding with particular reference to plasma gas flow-induced dynamic pressure and the droplet transfer mode. Dynamic pressure was measured and compared with theoretical values. The transfer characteristics of droplets was examined with high speed camera and oscillograph. The effects of the shielding gas composition and the chemical composition of wire on the transfer characteristics were determined. A phenomenon peculiar to large current MIG arc welding was revealed as follows. (1) The dynamic pressure induced by plasma gas flow is reduced by large diameter wire. (2) The transition from streaming to globular transfer was found to be continuous with respect to welding current and arc voltage. (3) This transition occurred even when the arc voltage was increased at the constant current. (4) These tendency was particularly pronounced when the CO_2 content of shielding gas and Si content of wire were relatively high. A study was undertaken to clarify the mechanism of arc voltage dependency on droplet transfer mode. The vapourization of oxides from the surface of molten metal on the electrode tip should be considered a factor which governs the droplet transfer.
社団法人溶接学会の論文
1983-02-05