Numerical simulation of a new electroslag remelting technology with current conductive stationary mold

Abstract

Based on a new electroslag remelting technology with current conductive stationary mold (ESR-CCSM), a two-dimensional axisymmetric steady-state mathematical model is established to first research the situation that the current totally flows out of the mold to power. With different boundary conditions of electromagnetic phenomena, the coupled electromagnetic field, flow field and temperature field are calculated to study distribution characteristics for traditional ESR and ESR-CCSM respectively. The results show that the magnetic field intensity of ESR-CCSM increases from the side of the symmetry axis and the baseplate to the side of the lateral surface of electrode and the free surface of slag. The current density and Joule heating between the electrode corner and the mold wall for ESR-CCSM are obviously higher than that for traditional ESR, and the temperature distribution of slag pool is more uniform. Compared to traditional ESR, the cylindrical section height of metal pool for ESR-CCSM is bigger, helping to gain smoother surface. Moreover, the metal pool of ESR-CCSM becomes shallower and the columnar crystal angle is smaller, propitious to obtain crystallization structure with a tendency to axial direction. Through comprehensive analysis, the optimal current parameter for a 350 mm diameter ingot of H13 die steel with ESR-CCSM is 5500 A. The in-situ experiment illustrates that the ingot surface is smooth. The columnar crystal growth is quite developed and the columnar crystal angle is mainly between 20° and 25°, tending to axial direction, much smaller than that for traditional ESR, which indicates that the H13 ingot produced by ESR-CCSM owns both good surface quality and solidification quality.