A Numerical Investigation on the Electrochemical Behavior of CaO and Al2O3 in the ESR Slags

Abstract

Field structures including electromagnetic, concentration of ions, and flow fields in an ESR-like process composed of a graphite crucible containing a molten slag, air, and an iron electrode are computed. Both CaF 2-(mass pct 2) CaO and CaF 2-(mass pct 2) Al 2 O 3 slags are examined. Tertiary current distribution is calculated. Therefore, polarization overpotential and Faradic reactions at metal-slag interface are considered using Tafel law, whereas transport of ions in the bulk of slag is determined through Nernst-Planck equations. The main goal is to shed light on the invisible phenomena such as magnetohydrodynamics caused by transport of ions, electrical conductivity of CaF 2-based slag using additives (e.g., CaO or Al 2 O 3), and the role of complexation of ions (e.g., AlO 3À 3) in the molten slag applied to the ESR. An explanation is given for the observation of higher oxygen content in the metal using Al 2 O 3 than that using equivalent amount of CaO in the CaF 2-based slag of a DC-operated ESR.

Investigation of effect of electrode polarity on electrochemistry and magnetohydrodynamics using tertiary current distribution in electroslag remelting process

“…( 9) through Eq. ( 13) as listed in Table 1, are utilized to determine electric current density field in the slag considering tertiary current distribution [31]. The conservation of electric current density, Eq.…”

“…Boundary conditions of electric potential and concentration of ions are interdependent [31]. The total mass flux of non-reacting ions (F À ; O 2À ) is zero at all boundaries enclosing the slag.…”

“…The positive sign is used if the electrode is anodic, and the negative sign is used if the electrode is cathodic. The electric potential at the interface between slag and anode/cathode is assigned using Tafel law as described in assumption (v) to account for the electric double layer formation and, consequently, the overpotential [31]. The relationship between overpotential and current density is plotted in Fig.…”

Precipitation Behavior of Nitride Inclusions in K418 Alloy under the Continuous Unidirectional Solidification Process

“…15) Many studies have reported the precipitation and removal behaviors of inclusions during solidification of steel. [16][17][18][19][20] A variety of techniques have been employed to remove inclusions from alloys, including vacuum induction melting (VIM), 21,22) elctroslag remelting (ESR), [23][24][25] Vacuum arc remelting (VAR), [26][27][28] Electron beam melting (EBM), 29,30) Hydrogen plasma arc melting (HPAM) 31,32) and double-melting or triple-melting processes. 33) Although most of the inclusions can be removed by these methods, there are drawbacks to these processes, such as the solidification defects, high energy consumption, time-consuming, and losses of high vapor pressure alloying elements.…”

Simulation of Solidification Structure During Vacuum Arc Remelting Using Cellular Automaton−Finite Element Method

“…[2,3] However, improper melting parameters may result in metallurgical defects, such as macrosegregation, porosities, and beta flecks. [4][5][6] Due to the high temperature of the smelting process, the experimental study was under restriction. The modeling study of the VAR process was used to obtain the optimal parameters for improving the quality of the ingot.Kondrashov et al [7] developed a simple heat model of the VAR process neglecting the magnetohydrodynamic phenomena in the molten pool.…”