Abstract:Abstract: Numerical simulation and analysis of the influence of electrode shrinkage cavity on electroslag remelting (ESR) process of a 430mm diameter ingot of IN718 alloy were carried out using the self-developed ESR process model. Electromagnetic fields of ESR system were simulated with specially designed various shape and size of cavity in the electrode. The results show that the changed contacting area between the electrode and the slag, owing to the cavity, plays the predominant role on the distributions of the Joule heat and electromagnetic force in the slag, while the effect of axial dimension change of the shrinkage cavity is negligible. Constant melt rate ESR processes were simulated for the different radius cavity situations. It is shown that, at a constant melt rate, no effect of shrinkage cavity on the ESR process can be seen as its radius is less than 0.025 m, and only minute influence on the slag flow when the radius reaches 0.05 m. As the radius increases over 0.05 m, increasingly evident influence on the slag zone appears with the center downward flow weakened and temperature risen. Nevertheless, there is no obvious influence of the cavity on the ingot including the melt pool and mush zone. There are nonlinear relations between the shrinkage cavity radius and the ESR melting parameters including current and power, with a critical value about 0.05 m for the radius. Below the critical value, faint or even no change of the parameters appears, while, above the value, the parameters of power and current soon turn into high speed increase, approximately in a linear manner. From the standpoint of process control stability, the shrinkage cavity radius should be controlled less than 0.05 m.