Effects of Arc Current and Electrode Size on Electrode Erosion in ac Plasma Torches

摘要

Heavy erosion of the electrode is a problem in using as plasma torches. In a series of our studies, The effects of electrode stem size (diameter and length) and tip shape on the electrode erosion were clarified at a low current of 200 A. In this paper, on the basis of the 200-A data, in order to reduce the electrode erosion with the current increased, the effects of current and electrode size on electrode erosion were clari- fied experimentally and analytically between 100 and 550 A. The electrode used was of solid type and the material Was tungsten containing 2 wt/100 of lanthanum oxide. The Plasma gas was argon. Main results are as follows.