Effect of arc parameters on metal transfer in consumable electrode melting during the VAR process by numerical investigation

Abstract

In this paper, a transient integrated model is proposed to investigate the liquid metal transfer mechanism during the consumable electrode melting process of vacuum arc remelting (VAR). The main arc parameters such as arc distribution, arc length and current intensity all have an obvious influence on electrode melting. This model is first validated and then applied to simulate the electrode melting under different arc parameters. The numerical results show that the droplet transfer is the only metal transfer mode throughout the electrode tip at the diffuse arc, a long arc length (50 mm) and a small current intensity (4760 A). The metal transfer mode is mainly drip short with little proportion of droplet transfer at the short arc length (10 mm), and the drip short can only be formed at the electrode centre under both constricted centric arcs and both larger current intensities. The concentration of arc heating, short arc length and large current intensity can all lead to a higher electrode melting rate. The predicted maximum melting rate is 11.48 kg/min at the 10 mm arc and the minimum melting rate is 4.96 kg/min at 4760 A under the specific operating conditions studied.