3D Thermo-Mechanical Modelling of Wheel and Belt Continuous Casting

Wire rod is produced by hot-rolling a bar of metal coming from a wheel/belt continuous casting process. This kind of process, e.g. Properzi, is an elaborate process in which the molten metal is poured in a cooled rotating mould formed by the groove of a wheel and closed by a belt. In order to better understand the heat transfer phenomenon and solidified bar characteristics, depending on process parameters a three dimensional thermo-mechanical model has been developed. The model, based on the finite-element method, calculates the heat transfer coefficient of the air gap at the metal-mould interface as a function of the size of the gap determined by the bar contraction and wheel and belt thermal deformations. The air gap formation due to metal shrinkage and mould deformation is the main factor which determines the heat extraction. Wheel temperature measurements with thermocouple and belt temperature measurements with an infrared system were carried out to verify model results. Attempts were also made to measure a liquid pool profile using doping with copper rich alloy. The model shows the effect of the casting temperature and the rotation speed on the air gap formation and resulting temperature and stress fields. The model can be applied to issues such as maximising wheel and belt life and minimising solidification defects.

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Heat Transfer Coefficient Determination in a Gravity Die Casting Process with Local Air Gap Formation and Contact Pressure Using Experimental Evaluation and Numerical Simulation

International Journal of Metalcasting ◽

10.1007/s40962-021-00663-y ◽

2021 ◽

Author(s):

T. Vossel ◽

N. Wolff ◽

B. Pustal ◽

A. Bührig-Polaczek ◽

M. Ahmadein

Keyword(s):

Heat Transfer ◽

Contact Pressure ◽

Local Heat Transfer ◽

Casting Process ◽

Local Heat ◽

Air Gap ◽

Gap Formation ◽

Transfer Coefficients ◽

Heat Transfer Coefficients ◽

Die Casting Process

AbstractAnticipating the processes and parameters involved for accomplishing a sound metal casting requires an in-depth understanding of the underlying behaviors characterizing a liquid melt solidifying inside its mold. Heat balance represents a major factor in describing the thermal conditions in a casting process and one of its main influences is the heat transfer between the casting and its surroundings. Local heat transfer coefficients describe how well heat can be transferred from one body or material to another. This paper will discuss the estimation of these coefficients in a gravity die casting process with local air gap formation and heat shrinkage induced contact pressure. Both an experimental evaluation and a numerical modeling for a solidification simulation will be performed as two means of investigating the local heat transfer coefficients and their local differences for regions with air gap formation or contact pressure when casting A356 (AlSi7Mg0.3).

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Conjugate Heat Transfer and Effects of Interfacial Heat Flux During the Solidification Process of Continuous Castings

Journal of Heat Transfer ◽

10.1115/1.1560146 ◽

2003 ◽

Vol 125 (2) ◽

pp. 339-348 ◽

Cited By ~ 6

Author(s):

M. Ruhul Amin ◽

Nikhil L. Gawas

Keyword(s):

Heat Transfer ◽

Continuous Casting ◽

Cooling Rate ◽

Solidification Process ◽

Air Gap ◽

Gap Formation ◽

Continuous Casting Mold ◽

Withdrawal Velocity ◽

Multiphase Fluid Flow ◽

Multiphase Fluid

Multiphase fluid flow involving solidification is common in many industrial processes such as extrusion, continuous casting, drawing, etc. The present study concentrates on the study of air gap formation due to metal shrinkage on the interfacial heat transfer of a continuous casting mold. Enthalpy method was employed to model the solidification of continuously moving metal. The effect of basic process parameters mainly superheat, withdrawal velocity, mold cooling rate and the post mold cooling rate on the heat transfer was studied. The results of cases run with air gap formation were also compared with those without air gap formation to understand the phenomenon comprehensively. The current study shows that there exists a limiting value of Pe above which the effect of air gap formation on the overall heat transfer is negligible.

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The Effect of Air Gap between Casting and Water-Cooled Mold on Interface Heat Transfer Coefficient

Materials Science Forum ◽

10.4028/www.scientific.net/msf.893.174 ◽

2017 ◽

Vol 893 ◽

pp. 174-180 ◽

Cited By ~ 2

Author(s):

Yi Dan Zeng ◽

Qing Hu Yao ◽

Xia Wang

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Solidification Process ◽

Casting Process ◽

Air Gap ◽

Gap Formation ◽

Interface Heat Transfer Coefficient ◽

Interface Heat Transfer ◽

Interface Heat

Water-cooled casting is a new casting process. It allows even large castings to solidify rapidly, thereby reducing segregation and grain refinement. It has drawn the attention of both domestic and foreign businesses. Heat transfer at the casting/water-cooled mold interface controls the cooling rate of the casting. During the solidification process, because of the contraction that takes place during casting, an air gap can form between the casting and the water-cooled mold. This air gap hinders heat transfer between the casting and the mold, leading to a rapid drop in the interface heat transfer coefficient (IHTC). The purpose of the present study was to assess the effects of the width of the air gap and the duration of gap formation on IHTC. During the experiment, the casting temperature curve was determined in the presence of the interface air gap, and then inverse calculation was performed using PROCAST software to determine the IHTC of casting/water-cooled mold. Results showed that, after the formation of the air gap, IHTC first exhibited a rapid decrease, followed by an increase and then another decrease; IHTC was found to decrease as gap width increased and as the duration of gap formation increased.

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An asymptotic model for the formation and evolution of air gaps in vertical continuous casting

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2008.0467 ◽

2009 ◽

Vol 465 (2105) ◽

pp. 1617-1644 ◽

Cited By ~ 29

Author(s):

M. Vynnycky

Keyword(s):

Continuous Casting ◽

Moving Boundary ◽

Three Dimensional ◽

Air Gap ◽

Parabolic Partial Differential Equation ◽

Asymptotic Model ◽

Gap Formation ◽

Type Boundary ◽

Almost All ◽

Type Boundary Condition

The formation of an air gap at the mould–metal interface in vertical continuous casting has long been known to have a detrimental effect on the efficiency of the process, and has therefore attracted attempts at mathematical modelling. While almost all current efforts consist of complex three-dimensional numerical simulations of the phenomenon, this paper considers instead an asymptotic model that captures the essential characteristics. The model is thermomechanical and is derived for a geometry, where the generalized plane strain approximation is appropriate. Although two-way coupling between the thermal and mechanical problems is accounted for, it is found that the problems decouple at leading order anyway, and that the thickness of the air gap does not depend on the constitutive relation used for describing the inelastic strains. Furthermore, a criterion for the onset of air-gap formation is derived in terms of the process operating parameters. Mathematically, we obtain a moving boundary problem for a parabolic partial differential equation with a degenerate initial condition and a non-standard Neumann-type boundary condition. Sample computations are performed using parameters for the continuous casting of the copper, and the results, qualitative trends and possible extensions are discussed.

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Heat Transfer and Solidification Model of Slab Continuous Casting Based on Nail-Shooting Experiments

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1088.153 ◽

2015 ◽

Vol 1088 ◽

pp. 153-158 ◽

Cited By ~ 1

Author(s):

An Gui Hou ◽

Yi Min ◽

Cheng Jun Liu ◽

Mao Fa Jiang

Keyword(s):

Heat Transfer ◽

Continuous Casting ◽

Liquid Core ◽

Casting Process ◽

Soft Reduction ◽

Slab Continuous Casting ◽

Solidification Model ◽

Core Length ◽

Measurement Results ◽

Heat Transfer And Solidification

A heat transfer and solidification model of slab continuous casting process was developed, and the nail-shooting experiments were carried out to verify and improve the prediction accuracy. The comparison between the simulation and the measurements results showed that, there exists difference between the model predicted liquid core length and the calculated liquid core length according to the measurement results of the solidification shell thickness. In the present study, the value of constant a in the heat transfer coefficient calculation formula was corrected through back-calculation, results showed that, the suitable value of a is 31.650, 33.468 and 35.126 when the casting speed is 0.8m·min-1, 0.9m·min-1 and 1.0m·min-1 respectively, which can meet the liquid core length of the measurement results. The developed model built a foundation for the application of dynamic secondary cooling, and dynamic soft reduction.

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Predicting heat extraction due to boiling in the cooling channels during the pressure die casting process

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406001523119 ◽

2000 ◽

Vol 214 (3) ◽

pp. 465-482 ◽

Cited By ~ 7

Author(s):

L D Clark ◽

I Rosindale ◽

K Davey ◽

S Hinduja ◽

P J Dooling

Keyword(s):

Heat Transfer ◽

Forced Convection ◽

Die Casting ◽

Casting Process ◽

Nucleate Boiling ◽

Heat Extraction ◽

Film Boiling ◽

Cooling Channels ◽

Die Casting Process ◽

Pressure Die Casting

The effect of boiling on the rate of heat extraction by cooling channels employed in pressure die casting dies is investigated. The cooling effect of the channels is simulated using a model that accounts for subcooled nucleate boiling and transitional film boiling as well as forced convection. The boiling model provides a continuous relationship between the rate of heat transfer and temperature, and can be applied to surfaces where forced convection, subcooled nucleate boiling and transitional film boiling are taking place in close proximity. The effects of physical parameters such as flow velocity, degree of subcooling, system pressure and bulk temperature are taken into account. Experimental results are obtained using a rig that simulates the pressure die casting process. The results are compared with the model predictions and are found to show good agreement. Instrumented field tests, on an industrial die casting machine, are also reported. These tests show the beneficial effects of boiling heat transfer in the pressure die casting process, including a 75 per cent increase in the production rate for the test component.

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