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JOM

, Volume 71, Issue 2, pp 744–753 | Cite as

Effects of Mold Current on Slag Skin and Heat Flow Distribution During Electroslag Remelting at Given Power Input

  • Jia Yu
  • Fubin Liu
  • Huabing LiEmail author
  • Zhouhua Jiang
  • Kui Chen
  • Xin Geng
CFD Modeling and Simulation in Materials Processing
  • 48 Downloads

Abstract

A transient model including the electromagnetic field, fluid flow, and heat transfer has been developed based on the volume-of-fluid model and dynamic mesh technique. At given power input, two cases were simulated to investigate the effects of the mold current on the slag skin and heat flow distribution. The calculated melt rate and slag skin thickness were compared with measurements to validate the model. At given power input, with the mold current, the slag–metal pool interface shows a higher temperature, resulting in a thinner slag skin of 1.2 mm. Due to the more uniform slag temperature, the heat flow to the slag/mold interface reaches 34.7%, resulting in a low melt rate of 75 kg/h. In a laboratory-scale electroslag remelting unit, the heat transferred to the metal pool by convection approached 28% of the power input, independent of whether the mold current is considered or not.

List of Symbols

\( \vec{H} \)

Magnetic field intensity (A/m)

\( H_{\theta } \)

Magnetic field intensity in azimuthal direction (A/m)

\( \hat{H}_{\theta } \)

Complex amplitude of magnetic field intensity in azimuthal direction (A/m)

r

Radial coordinate

z

Axial coordinate

t

Time (s)

\( \vec{J} \)

Current density vector (A/m2)

\( \vec{V} \)

Velocity (m/s)

I

Current (A)

j

Imaginary unit

P

Pressure (Pa)

\( f_{\text{l}} \)

Liquid fraction

Amush

Mushy zone constant (Pa s/m2)

d1

Primary dendritic arm space (m)

\( \vec{V}_{\text{cast}} \)

Cast velocity (m/s)

\( \vec{g} \)

Gravity acceleration (m2/s)

Pt

Transient power input (kW)

P0

Target power input (kW)

\( Q_{\text{Joule}} \)

Joule heating (W/m3)

\( \vec{F}_{\text{e}} \)

Lorentz force (N/m3)

\( \vec{F}_{\text{d}} \)

Drag force for blocking the flow in mushy zone (N/m3)

L

Latent heat (J/kg)

\( k_{\text{eff}} \)

Effective thermal conductivity (W/(mK))

\( k_{\text{m}} \)

Thermal conductivity of electrode (W/(mK))

\( {\text{S}}_{\text{electrode}} \)

Cross-sectional area of electrode tip (m2)

m

Melt rate (kg/s)

\( H \)

Enthalpy (J/kg)

\( h \)

Sensible enthalpy (J/kg)

href

Reference enthalpy at the reference temperature Tref

\( T_{\text{ref}} \)

Reference temperature used for calculating sensible enthalpy (K)

T

Temperature (K)

T0

Reference temperature used for calculating buoyancy (K)

\( C_{\text{p}} \)

Heat capacity (J/(kgK))

Tl

Liquidus temperature (K)

Ts

Solidus temperature (K)

Greek Symbols

\( \sigma \)

Electric conductivity (\( \varOmega^{ - 1} \;{\text{m}}^{ - 1} \))

\( \mu_{0} \)

Permeability of vacuum (T m/A)

\( \rho \)

Density (kg/m3)

\( \rho_{0} \)

Reference density (kg/m3)

\( \rho_{q} \)

Density of phase q (kg/m3)

\( \mu \)

Dynamic viscosity (Pa s)

\( \alpha_{q} \)

Volume fraction of phase q

\( \varphi \)

Property of mixture phase property

\( \omega \)

AC frequency (Hz)

\( \beta \)

Thermal expansion coefficient (1/K)

Notes

Acknowledgements

This project was supported by the National Nature Science Foundation of China (Grant Nos. 51434004, U1435205, and 51674070), the Fundamental Research Funds for the Central Universities (Grant No. N162504006), and the Transformation Project of Major Scientific and Technological Achievements in Shenyang (Grant No. Z17-5-003).

Conflict of interest

The authors declare no conflict of interest.

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Copyright information

© The Minerals, Metals & Materials Society 2018

Authors and Affiliations

  • Jia Yu
    • 1
  • Fubin Liu
    • 1
  • Huabing Li
    • 1
    Email author
  • Zhouhua Jiang
    • 1
  • Kui Chen
    • 1
  • Xin Geng
    • 1
  1. 1.School of MetallurgyNortheastern UniversityShenyangChina

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