Abstract
Joule heating of welding wire is very important for stabilizing arc discharge. Joule heating of bulk wire is simple, has been estimated in many papers. On the other hand, Joule heating at sliding contacts during welding has not been estimated exactly. In this paper, current branch and contact resistance were measured during welding, and the temperature of wire above molten droplet was calculated using the measured values. Contact resistance of the main sliding point effected the average temperature of wire, and current branch effected the deviation temperature of wire. Joule heating power at sliding contacts of non-Cu-coated and Cu-coated solid wire is 108W and 59W respectively. Joule heating power of bulk wire is 829 W and 902 W respectively, so Joule heating power of the sliding contacts can change the average and deviation of melting speed during welding.
