Experimental investigation on the dynamics of cathode spots in arc plasma descaling

Abstract

Abstract In the ferrous metallurgical industry, removal of the oxide layer on steel surface (i.e. descaling) with low pressure arc plasma is an environmentally friendly method. In this paper, high speed camera and oscilloscope were employed to diagnose the process of arc decaling. The evolution of cathode spots morphologies and the property of arc voltage fluctuations were investigated for different discharge conditions. The motion and lifetime of the cathode spots are affected obviously by discharge parameters such as pressure, electrode gap and arc current. The lifetime and velocity of the cathode spots are essentially depended on the properties of the substructure of the cathode spot. The fluctuations of arc voltage are directly associated with the dynamics of the cathode spots, and there are large voltage fluctuations for short spot lifetime, large velocity of the spots and poor conditions for spot ignition.