Cathode-arc-anode behavior in cooling-induced cathode-focusing GTA system: A unified numerical model

Abstract

A gas tungsten arc (GTA) is an important heat source for manufacturing, cooling to the tungsten electrode has a critical influence on the cathode-arc-anode behavior because cooling-induced cathode-focusing (CICF) effect forms. In this research, a unified arc-electrode model is established to predict the influence of tungsten electrode cooling degree on heat transfer behavior in the cathode-arc-anode system. The results show that enhancing the cooling degree of the tungsten electrode can: (1) increase the arc voltage and arc power; (2) increase the arc pressure and the heat transferred to the anode and improve the arc penetration ability; (3) but slightly increase the heat transfer to the cathode tungsten rod at a given arc current. The developed model is validated by available experimental data. The research results deepen the understanding to the CICF effect and provide guidance for increasing optimizing the GTA torch structure to improve the arc penetration ability.