Numerical Simulation Of Droplet Behavior During Electroslag Remelting Process

Inclusions are removed and ingots quality is improved effectively by electroslag remelting process. The melting of consumable electrodes and dripping process of droplet are the central phenomena, the droplet diameter influence the efficiency of inclusion removing. The flow field distribution caused by the phenomena mentioned above determines the temperature field distribution in slag pool and the molten pool shape. Droplets finally influence the ingot quality. Mathematical models, including the electrode melting model and the molten pool depth and shape models, were established for the simulation of the ESR process by the volume of fluid technique by coupling electromagnetic field equations, energy equations and flow equations. After that, the effect of operating variables, such as the voltage, the filling ratio and the pool/slag interfacial tension, on the droplets behaviors and electrode melting velocities on the molten steel pool were investigated. The results indicate that:(1) Under the model conditions, when remelting voltage is 30 V,35 V and 40 V, respectively, with the increasing of voltage, at the electrode tip droplet increases from one to two at the beginning of remelting. The droplet diameter increases from 10.56 mm to 11.55 mm, then to 11.84 mm. The electrode remelting rate increases from 0.68 kg-min-1 to 0.86 kg-min-1, then to 1.47 kg·min-1.(2) Under the model conditions, the filling ratio values 0.5,0.6,0.7 and 0.8. With filling ratio increasing, the droplet diameter increases from 11.5 mm to the maximum value of 11.90 mm when filling ratio is less than 0.6. After that, with filling ratio increasing, the droplet diameter decreases from the maximum value to 11.58 mm, then to the minimum value 8.71 mm.(3) Under the model conditions, the interfacial tension is 0.9 N·m-1,1.2 N·m-1 and 1.4 N·m-1, respectively. With the increasing of interfacial tension, the droplet diameter increased from 10.56 mm to 11.48 mm, then to 12.27 mm. (4) Under the model conditions, electrode remelting velocities values 0.68 kg·min-1,0.86 kg·min-1 and 1.47 kg·min-1. With the increasing of melting velocity, the depth of pool increased from 40 mm to 65 mm, then up to 112 mm. The mushy zone width in the ingot center increased from 7 mm to 16 mm, then up to 51 mm. The local solidification time increased from 63 s to 133.3 s, then up to 231.8 s.