Numerical simulation of the formation and the dripping of droplet in the Electroslag Remelting process

The formation and dripping behavior of droplets in the process of the electroslag remelting with two series-connected electrodes (TSCE-ESR) has an important influence on the optimization of power supply parameters and the purity of the electroslag ingot. In this article, through numerical simulation based on the VOF (volume of fluid) model, combined with the transparent experimental device for physical simulation, the mechanism of metal droplet formation and the effect of the filling rate on its droplet behavior were studied. The results showed that the proximity effect, instead of the skin effect, is a major factor influencing droplet formation in TSCE-ESR process. The proximity effect makes the region inside the two electrode tip melt first, and the molten steel converges at the electrode tips to form a droplet source. The process of droplet formation and dropping can be divided into three stages: formation of molten layer, droplet stretching and necking, and detachment. In the stage of droplet stretching and necking, the increase in the contact area between the droplet and the slag and the instantaneous increase of the current provide good thermodynamic and dynamic conditions for the removal of non-metallic inclusions. After the droplet drops into the slag pool, it promotes the flow of slag and improves the heat and mass transfer efficiency of the slag/metal interface. The relatively large filling rate can form smaller and dispersed droplets, which improves the refining effect. At the same time, the increase of the filling rate can improve the input power and the electrode remelting rate.

Section: Introductionsupporting

confidence: 57%

Droplet Formation and Dripping Behavior during the Electroslag Remelting Process with Two Series-Connected Electrodes

Tong

Zang

et al. 2020

“…Metals 2020, 10,658 where Q represents the heat absorbed by the droplet, m e indicates the electrode melting rate, C p denotes heat capacity of liquid steel, T dp is the temperature of the droplet, T L represents liquidus temperature, T me represents the melting temperature of the electrode.…”

Section: Governing Equation For Dropletmentioning

confidence: 99%

“…However, the two actually affected each other, so this simulation method would also lead to inaccurate simulation results. Liu [10] established a mathematical model of droplet behavior of the electroslag remelting process based on magnetohydrodynamic. The electromagnetic force and joule heat in the process of droplet formation and dropping were studied in detail.…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Mathematical Model of Electroslag Remelting with Two Series-Connected Electrodes Based on Sequential Coupling Simulation Method

Tong

Zang

et al. 2020

A comprehensive mathematical model of electroslag remelting with two series-connected electrodes (TSCE-ESR) was constructed based on sequential coupling method. The influence of droplet effect on electroslag remelting process (ESR) was considered in this model. Compared with one-electrode electroslag remelting (OE-ESR), the multi-physics field, droplet formation and dripping behavior, and molten metal pool structure of TSCE-ESR process were studied. The results show that during the process of TSCE-ESR, the proximity effect of the electrodes suppresses the skin effect, and Joule heat is concentrated in the area between the two electrodes of slag pool, making the temperature distribution of the slag pool more uniform. The heat used to melt the electrode in the process of TSCE-ESR accounts for about 34% of the total Joule heat, which is lower than the OE-ESR (17%). Therefore, it makes a higher melting rate and a smaller droplet size in the process of TSCE-ESR. Compared with OE-ESR, TSCE-ESR process can realize the unification of higher melting rate and shallow flat molten metal pool. Compared with the results without droplet effect, it is found that in the simulation results with droplet effect, the depth and the cylindrical section of molten metal pool increased, and the width of the mushy zone is significantly reduced, which is more consistent with the actual electroslag remelting process.

“…Wang F et al [25] took the electrode, slag pool and ingot in the electroslag remelting process as research objects, established a finite element model of an electromagnetic field and analyzed the distribution of the magnetic field, electromagnetic force, current density and Joule heat density. Liu Y et al [26] obtained the distribution of an electromagnetic field and joule heat field in the stable electroslag remelting process by using finite element analysis software and analyzed the distribution of the shape, temperature and velocity field of the metal melt pool in the process of electroslag remelting under basic control parameters. Jing X et al [27,28] established a mathematical model of the electroslag remelting of hollow ingot by conducting a crystallizer, calculated the influence of different power supply methods on the temperature field of an electroslag remelting hollow ingot system and then analyzed the influence of the electric field system and temperature field distribution on the quality of the hollow ingot.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Electromagnetic Field in Slab Electroslag Remelting Process with Double Electrode Series

Li,

Jing,

Sun

2023

In this paper, a mathematical model of an electromagnetic field during an electroslag remelting process of industrial-scale slab was established using a Maxwell 3D module in Ansys Electromagnetics Suite. The distribution characteristics of the magnetic field intensity, current density and Joule heat density during the electroslag remelting process were analyzed in detail. On this basis, the influence of the current frequency on the electroslag remelting process of an industrial scale is studied, and the influence of process parameters such as the slag pool depth, electrode insertion depth and ingot height on the electromagnetic field is also considered. The results show that the Joule heat generated in the slag pool is much greater than that of the electrode and the ingot. The maximum Joule heat is located at the contact between the electrode corner and the slag pool, and the Joule heat near the middle of the two electrodes is greater than the rest. With the increase in the current frequency, the current density distribution in the slag cell is basically unchanged. The current density inside the two electrodes increases obviously with the current frequency. When the current frequency increases from 10 Hz to 50 Hz, the maximum current density at the inner surface of the electrode increases by 14.7%. The current distribution at the lower side of the electrode in the slag pool is relatively uniform, and the current density in this region decreases with the increase in the height of the slag pool and the increase in the depth of the electrode inserted into the slag pool.