Optical investigation of the behavior of the electric arc and the metal transfer during vacuum remelting of a Ti alloy

Chapelle, Pierre; Noël, Cédric; Risacher, Aurore; Jourdan, Julien; Jardy, Alain

doi:10.1016/j.jmatprotec.2014.04.024

Cited by 16 publications

(12 citation statements)

References 7 publications

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…Modeling VAR process is very challenging and controversial as the process involves a wide range of physical phenomena and their interactions. Modeling activities are required to study each phenomenon including formation and movement of cathode spots at the tip of electrode, [1][2][3][4][5][6][7] the vacuum plasma, [4,5,[8][9][10][11][12][13][14][15][16][17][18][19][20] the electric current transferred directly between the electrode and mold, known as ''side-arcing,'' [12,18,[21][22][23][24] the thermal radiation in the vacuum region, [21,25,26] melting of the electrode, [8,[27][28][29][30][31][32][33][34][35][36][37][38] the influence of electromagnetic field on the flow known as magnetohydrodynamics (MHD) in the molten pool, [39][40]…”

Section: Introductionmentioning

confidence: 99%

“…[28,66] The mechanism of droplet transfer from the tip of melting electrode to the molten pool is dependent on the gap length. Chapelle et al [36] postulated three steps including growth, rupture, and erosion of metallic droplets when the gap length is large. Furthermore, they found that the voltage signal is associated with the metal transfer mechanism.…”

Section: Introductionmentioning

confidence: 99%

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

Karimi-Sibaki

Kharicha

et al. 2019

Metall Mater Trans B

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Main modeling challenges for vacuum arc remelting (VAR) are briefly highlighted concerning various involving phenomena during the process such as formation and movement of cathode spots on the surface of electrode, the vacuum plasma, side-arcing, the thermal radiation in the vacuum region, magnetohydrodynamics (MHD) in the molten pool, melting of the electrode, and solidification of the ingot. A numerical model is proposed to investigate the influence of several decisive parameters such as arc mode (diffusive or constricted), amount of side-arcing, and gas cooling of shrinkage gap at mold-ingot interface on the solidification behavior of a Titanium-based (Ti-6Al-4V) VAR ingot. The electromagnetic and thermal fields are solved in the entire system including the electrode, vacuum plasma, ingot, and mold. The flow field in the molten pool and the solidification pool profile are computed. The depth of molten pool decreases as the radius of arc increases. With the decreasing amount of side-arcing, the depth of the molten pool increases. Furthermore, gas cooling fairly improves the internal quality of ingot (shallow pool depth) without affecting hydrodynamics in the molten pool. Modeling results are validated against an experiment.

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“…4 Therefore, it becomes important to study the mechanism of material transfer in electric sliding of the contact strip against the contact wire. In the literature, most of researches on the material transfer were performed under the condition of DC, 22,23 or without electric current. 24–28 The electric power used in the high-speed railway is AC.…”

Section: Introductionmentioning

confidence: 99%

“…The microparticle removal mechanism and the heat energy inhomogeneous mechanism of friction pairs are considered to be two main mechanisms for material transfer in the condition of DC. 22,23 However, it needs reexamining whether they are still the mechanisms for material transfer or not in the condition of AC. Therefore, it is significant to study the mechanism of material transfer in the electric sliding process of pantograph-catenary systems.…”

Section: Introductionmentioning

confidence: 99%

Study on material transfer in the process of contact strips rubbing against a contact wire with electric current

Chen

Gao

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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A series of experimental tests on a block-on-ring tester were carried out to obtain a new understanding of severe material transfer in the process of contact strips rubbing against a contact wire with electric current. Three types of contact strip materials including an aluminum-based strip, a copper-based strip, and a pure carbon strip are tested in electric sliding against two contact wire materials including a pure copper contact wire and a copper–silver alloy contact wire. Test results show that there are serious material transfers in these three different friction couples in electric sliding. The aluminum-based strip has the severest material transfer, followed by the copper-based strip. The pure carbon strip has the minimum material transfer. It is found that the material transfer increases with the increase of the sliding speed, the arc discharge intensity, and the contact pressure. In the presence of electric current, contact strip materials are always transferred to the contact wire.

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Optical investigation of the behavior of the electric arc and the metal transfer during vacuum remelting of a Ti alloy

Cited by 16 publications

References 7 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

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

Study on material transfer in the process of contact strips rubbing against a contact wire with electric current

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