A Parametric Study of the Vacuum Arc Remelting (VAR) Process: Effects of Arc Radius, Side-Arcing, and Gas Cooling

Karimi-Sibaki, Ebrahim; Kharicha, Abdellah; Wu, Menghuai; Ludwig, Andreas; Boháček, Jan

doi:10.1007/s11663-019-01719-5

Cited by 32 publications

(15 citation statements)

References 77 publications

(106 reference statements)

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“…The effect of the metal crown for-mation (~20 mm) at the top edge of the ingot on the electromagnetic field is considered. [14] (iii) The top surface of ingot (vacuum-ingot interface) is assumed to be stationary and flat. (iv) The formation of droplets at the tip of electrode and the dripping of droplets in the vacuum are not modeled.…”

Section: Modelingmentioning

confidence: 99%

“…(v) The arc is implicitly modeled considering a Gaussian distribution of electric current density as a function of radial position on the tip of the electrode and the top of the ingot. [14,[32][33][34]…”

Section: Modelingmentioning

confidence: 99%

“…Darcy's law [35] is applied to account for interdendritic flow inside the ingot considering the drag resistance force in the mushy zone that involves casting speed (u s ) and permeability (K). [14] For that purpose, the isotropic model of Kozeny-Carman is utilized. [14,36] Computations of the components of Lorentz force (F ¼ F r ; F h ; F x ð Þ ) are described after introducing the governing equations of the electromagnetic field.…”

Section: ½4mentioning

confidence: 99%

“…[14] For that purpose, the isotropic model of Kozeny-Carman is utilized. [14,36] Computations of the components of Lorentz force (F ¼ F r ; F h ; F x ð Þ ) are described after introducing the governing equations of the electromagnetic field.…”

Section: ½4mentioning

confidence: 99%

“…Diverse phenomena exist in VAR, including cathode spots at the tip of electrode, [1,2] the vacuum plasma, [3][4][5] the thermal radiation in the vacuum, [6] melting of the electrode, [7,8] solidification of the ingot, [9][10][11] and the interplay between the electromagnetic field and the flow as known as magnetohydrodynamics (MHD) in the melt pool. [12][13][14] The electric current flowing through the entire system produces a self-induced magnetic field dominantly in the azimuthal direction. An external axial magnetic field (AMF) is often deliberately introduced to stabilize the arc.…”

Section: Introductionmentioning

confidence: 99%

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A Numerical Study on the Influence of an Axial Magnetic Field (AMF) on Vacuum Arc Remelting (VAR) Process

Karimi-Sibaki

Kharicha

Abdi

et al. 2021

Metall Mater Trans B

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A comprehensive numerical model is proposed to study the influence of an axial magnetic field (AMF) on the solidification behavior of a Titanium-based (Ti–6Al–4V) vacuum arc remelting (VAR) ingot. Both static and time-varying AMF are examined. The proposed 2D axisymmetric swirl model includes calculating electromagnetic and thermal fields in the entire system composed of the electrode, vacuum plasma, ingot, and mold. A combination of vector potential formulation and induction equation is proposed to model the electromagnetic field accurately. Calculations of the flow in the melt pool and solidification of the ingot are also carried out. All governing equations are presented in cylindrical coordinate. The presence of a weak AMF, such as the earth magnetic field, can dramatically influence the flow pattern in the melt pool. The “Electro-vortex flow” is predicted ignoring AMF or in the presence of a time-varying AMF. However, the flow pattern is “Ekman pumping” in the presence of a static AMF. The amount of side-arcing has no influence on the pool depth in the presence of an AMF. Modeling results are validated against experiments.

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Section: Modelingmentioning

confidence: 99%

Section: Modelingmentioning

confidence: 99%

Section: ½4mentioning

confidence: 99%

Section: ½4mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Numerical Study on the Influence of an Axial Magnetic Field (AMF) on Vacuum Arc Remelting (VAR) Process

Karimi-Sibaki

Kharicha

Abdi

et al. 2021

Metall Mater Trans B

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

Wang

Zhang

et al. 2021

steel research int.

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Vacuum arc remelting (VAR) is a secondary melting process for production of metal ingots. [1] In the vacuum condition, the alloy ingot as an electrode was melted by the electric arc and then molten drops fell into the mold. The VAR process was extensively utilized to improve the cleanliness, chemical homogeneity, and mechanical property of metal ingots. [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. The depth of the molten pool was predicted under different current intensities. Delzant et al. [1] established two models to calculate the thermal radiation of the ingot top during the VAR process. In the crude approach, only the radiative heat transfer between the ingot and the electrode tip was considered. In the detailed approach, all radiative exchanges between the ingot, electrode, and crucible wall were taken into account. Results of the detailed radiation model revealed that the radiative heat transfer of the ingot top was heavily dependent on the arc gap length and the electrode radius. Patel et al. [8] investigated the effect of processing parameters on molten pool profile, flow field, and segregation using a 2D mathematical VAR model. The molten pool profile was significantly affected by the magnetic field. The flow and overall segregation tendency increased with the increase in the magnetic field. Zagrebelnyy et al. [9] established a numerical model to study the segregation of the ingot during the VAR process. The strong flow field was induced by the high arc power resulting in severe macrosegregation. When the arc power was low, the flow was dominated by weaker buoyancy force, and less segregation was formed. Kou et al. [10] calculated the temperature field, fluid flow, and solidification structure of the Ti─6Al─4 V alloy ingot during the VAR process. When the heat radiation was considered, simulated columnar grains on the ingot top agreed well with the experimental results. Chapelle et al. [11] investigated the deformation of the free surface in the VAR process using CFD-based simulations. Two stirring modes were applied in the simulation. In the case of unidirectional stirring, the free surface was a concave dome shape. In the case of alternated stirring, periodic fluctuations of the liquid metal level were generated. Kermanpur et al. [12] established a multiscale

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Numerical Simulation of White Spot Formation in Vacuum Arc Remelting

Jiang

Zhang

2023

steel research int.

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Coupling fluid flow, heat transfer, solidification, and particle dissolution behavior, the white spot formation in the vacuum arc remelting process is simulated. The effect of particle initial diameter, dropping position, and dropping height on the remelting behavior is investigated. The results show that the particle from the electrode drops through the arc zone with gravity force and the diameter is reduced in the high‐temperature zone. As the diameter is lower than 5 mm, the particle completely dissolves and the white spot formation can be eliminated. The particle dissolution is less affected by the liquid pool depth, but it is mainly affected by the high‐temperature zone distribution, which is closely related to the electric arc generation. Because of the limited high‐temperature zone near the ingot side surface, the particle from the ingot crown is more difficult to remelt, compared with that from the electrode. Moreover, it is found that the dropping height obviously affects the particle remelting behavior. As the dropping height decreases from 25 to 0, the particle critical diameter that can fully dissolve increases from 4.2 to 6.6 mm.

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A Parametric Study of the Vacuum Arc Remelting (VAR) Process: Effects of Arc Radius, Side-Arcing, and Gas Cooling

Cited by 32 publications

References 77 publications

A Numerical Study on the Influence of an Axial Magnetic Field (AMF) on Vacuum Arc Remelting (VAR) Process

A Numerical Study on the Influence of an Axial Magnetic Field (AMF) on Vacuum Arc Remelting (VAR) Process

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

Numerical Simulation of White Spot Formation in Vacuum Arc Remelting

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