A Parametric Study of Slag Skin Formation in Electroslag Remelting

Yanke, Jeff; Krane, Matthew John M.

doi:10.1002/9781118830857.ch10

Cited by 12 publications

(10 citation statements)

References 8 publications

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“…The final term is Joule heating, where a is the electrical conductivity. The For simplicity, this model assumes that the thickness of the slag skin is uniform along the length of the ingot and slag cap, although predictions have shown that it does vary along the axial direction [9]. As long as the changes in skin thickness are gradual, the variation should have a small effect on the inverse predictions because the models measure the flux at the interior surface of the mold and make no assumption about the slag skin.…”

Section: Full Esr Model Implementationmentioning

confidence: 99%

“…Most models of the ESR process to date handle this boundary by developing an effective heat transfer coefficient using a thermal resistance network [2][3][4][5], similar to how the ther mal boundary conditions for the outer radius of the ingot in simu lations of vacuum arc remelting are formulated [6][7][8], with the added consideration of the slag skin. One exception is a study by Yanke and Krane [9] in which the slag skin solidification was simulated directly, and the boundary condition considered only the shrinkage gap and the copper mold. The difficulty in formulat ing the boundary condition for ESR lies primarily in the properties of the slag skin.…”

Section: Introductionmentioning

confidence: 99%

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The Use of Inverse Heat Conduction Models for Estimation of Transient Surface Heat Flux in Electroslag Remelting

Plotkowski

Krane

2015

Journal of Heat Transfer

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Three inverse heat conduction models were evaluated for their ability to predict the tran sient heat flux at the interior surface of the copper mold in the electroslag remelting (ESR) process for use in validating numerical ESR simulations and real-time control sys tems. The models were evaluated numerically using a simple one-dimensional (ID) test case and a 2D pseudo-ESR test case as a function of the thermocouple locations and sam ple frequency. The sensitivity of the models to measurement errors was then tested by applying random error to the numerically calculated temperature fields prior to the application of the inverse models. This error caused large fluctuations in the results of the inverse models, but these could be mitigated by implementing a simple SavitzkyGolay filter for data smoothing. Finally, the three inverse methods were applied to a fully transient ESR simulation to demonstrate their applicability to the industrial process. Based on these results, the authors recommend that the 2D control volume method described here be applied to industrial ESR trials.

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Section: Full Esr Model Implementationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Use of Inverse Heat Conduction Models for Estimation of Transient Surface Heat Flux in Electroslag Remelting

Plotkowski

Krane

2015

Journal of Heat Transfer

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“…Assuming an electrically insulator slag skin, Weber et al have shown that the difference between the slag liquidus and alloy liquidus temperatures is a critical parameter to determine the thermal field in the entire ESR process. Yanke et al used the Volume of Fluid (VOF) method to track the slag/metal interface and so allowing simulation of slag freezing to the mold (Figure ). They also neglected the possibility for the current to cross the slag skin.…”

Section: Special Topics In the Esr Processmentioning

confidence: 99%

“…The simulation is performed for alloy 718 considering the following composition for the slag: 70%CaF 2 –15%CaO–15%Al 2 O 3 . Reproduced from ref . with permission.…”

Section: Special Topics In the Esr Processmentioning

confidence: 99%

Review on Modeling and Simulation of Electroslag Remelting

Kharicha

Karimi-Sibaki

et al. 2017

steel research int.

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The Electroslag Remelting (ESR) is an advanced technology for the production of high quality materials, for example, hot work tool steels or nickel base alloys. In the past years, several models are developed aiming to predict the way in which the operational parameters affect the structure and chemical composition of the final ESR ingot. Proper modeling of this process depends on the ability of the model to predict the Multiphysics resulting from the complex coupling between many physical phenomena. This review includes the main findings starting from the 1970's, with a special focus on the results obtained in the period of 1999-2017. The difficulties related to the poorly known physical properties of ESR slags are discussed. Then, the main achievements in the field of electromagnetism, fluid flow, heat transfer, and solidification are also summarized. The review finishes by presenting the special topics representing the actual scientific frontiers, such as the physics of mold current, the importance of multiphase phenomena, and the difficulties in predicting the electrode melting rate.

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“…Weber et al developed a comprehensive model to investigate the solidification of molten slag and metal with the enthalpy method. Yanke et al explored the effects of current level and mold diameter on slag skin using the volume of fluid (VOF) model and neglected the difference between molten slag and slag skin in electrical conductivity. Hugo et al and Jardy et al demonstrated the effects of mold current on slag skin at the same current level and found that the slag skin thickness increased with the existence of mold current.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Dynamic Formation of Slag Skin and Heat Flow Distribution during the Electroslag Remelting Process

Liu

Kang

et al. 2018

steel research int.

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A 2D axisymmetric model is established to investigate the dynamic formation of slag skin and heat flow distribution during the electroslag remelting process. The growth of ingots is addressed with the dynamic mesh technique, and the volume of fluid model is employed to trace the slag/metal interface. The results indicate that the slag skin thickness at the slag/mold interface increases with the distance from the free slag surface, with a maximum thickness of 4 mm at the slag/pool interface. With the growth of ingot, the slag skin at the slag/pool interface is partially remelted by the hotter metal and finally solidifies around the solidified ingot with a thickness of 1 mm. The calculated percentage of heat flow is in reasonable agreement with the measurement. The loss of heat flow to the mold accounts for 67% of the power input, and approximately 28% of that power is absorbed by droplets in a laboratory scale ESR unit. The heat loss to slag/mold interface first increases with increasing slag temperature and then slowly decreases with decreasing slag bath height. The heat of the ingot primarily escapes from the baseplate at the initial stage. However, as the ingot grows, the heat loss in the radial gradually becomes dominant.

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A Parametric Study of Slag Skin Formation in Electroslag Remelting

Cited by 12 publications

References 8 publications

The Use of Inverse Heat Conduction Models for Estimation of Transient Surface Heat Flux in Electroslag Remelting

The Use of Inverse Heat Conduction Models for Estimation of Transient Surface Heat Flux in Electroslag Remelting

Review on Modeling and Simulation of Electroslag Remelting

Numerical Simulation of the Dynamic Formation of Slag Skin and Heat Flow Distribution during the Electroslag Remelting Process

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