A Study on Control of Deposition Rate in Hot-wire TIG Welding

Abstract

The optimum relation between welding current and wire melting rate for the high-speed hot wire GTA welding is decided and a new power control system is developed. The new system has two merits, one is that the power source is simplified by using a part of the arc current as the wire heating current, and the other is that a stable melting of wire is realized by monitoring the voltage drop across the wire extension. The results in this study are as follows. (1) The welding speed can be increased by pre-heating the wire. The effect of speed-up is promoted especially in the case that the bead width is enlarged by adding the hot wire deposit. (2) The optimum relation between welding current and wire melting rate for high speed welding is almost independent of the plate thickness. (3) In the new control system, the welding speed can be raised up to two times of that obtained with the cold wire GTA welding without troublesome adjustments of the power source. © 1986, JAPAN WELDING SOCIETY. All rights reserved.