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Tuesday, August 11, 2020 | History

2 edition of Heat transfer at the casting metal-mold interface during solidification. found in the catalog.

Heat transfer at the casting metal-mold interface during solidification.

Basil L. Coates

Heat transfer at the casting metal-mold interface during solidification.

by Basil L. Coates

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Published .
Written in English


About the Edition

To effect this investigation a novel apparatus was developed. This apparatus was instrumented with thermocouples, displacement sensors-LVDT (Linear Variable Differential Transformer) and electrical contact detection circuit. It not only provided the base for obtaining accurate temperature profiles in casting and chill; it also recorded data that helped in characterizing mold expansion and the detection, formation and development of an air gap in the latter stage of metal solidification.This investigation focused primarily on the effect of surface roughness on heat transfer coefficient values whilst exploring the dynamics and mechanisms of heat transfer at the casting metal-mold interface during solidification of liquid metal. Several experimental, computational and analytical techniques were developed and utilized. A cylindrical and horizontally oriented casting configuration with fixed metallostatic head was used. To evaluate quantitatively the effects of Surface Roughness, Thermal Conductivity and Contact Temperature on the heat transfer coefficient at the metal mold interface during the solidification of liquid metal is the object of this study.Data collected from experiments (using commercial purity aluminum and aluminum alloys (A319 and A356) against different chill materials including steel, cast iron and copper) was used as input into an Inverse Heat Transfer Code developed in the course of this work. Different surface roughness was applied to each chill material used. Consequently, surface roughness was observed to have varying degrees of effect depending on superheat, chill and alloy materials. Heat transfer coefficient values during the development of air gap initially suffer from a drastic reduction followed by a recovery to almost constant values. Generally, an increase in surface roughness results in the decrease of heat transfer coefficient at the metal-mold interface. Further, analysis of the heat transfer data revealed that two dominant heat transfer modes occur during air gap development: "conduction" followed by "convection" in the same order.

The Physical Object
Pagination259 leaves.
Number of Pages259
ID Numbers
Open LibraryOL20339351M
ISBN 100612917827

The %wt and %wt of Ti powder molten A at the raised temperature of o C was considered. Lin et al. [27] studied the interfacial heat transfer coefficient of metal moulding casting and. Therefore, the inverse heat conduction problem based on non-linear estimation technique of Chattopadhyay,() and Hu and Yu,(), has been adopted to determine the values of interface heat transfer coefficients, as a function of time during solidification of squeeze casting. Solidification of squeeze casting of aluminium involves phase.

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. The heat transfer from the shell is important because it determines how thick the shell is and, consequently, how strong the shell is. Four aspects of the heat transfer are considered here, namely, (i) horizontal heat transfer, (ii) shell solidification, (iii) vertical heat transfer and (iv) the variability in heat transfer. The horizontal heat.

Modelling of heat transfer and solidification processes in horizontal twin-roll casting of casting (TRC). During this process, the molten alloy is fed between two counter-rotating rolls uid and the solid region at the interface[5]. The largest amount of. The heat transfer to the mould is very important during casting and solidification. The formation of an air gap between the casting and the mould has a huge impact on the heat transfer. The relationship between variations in the heat transfer coefficient and the formation of an air gap has been investigated by a number of researchers [].


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Heat transfer at the casting metal-mold interface during solidification by Basil L. Coates Download PDF EPUB FB2

Narayan Prabhu and K.M. Suresh, Effect of superheat, Mold and Casting Materials on Metal/Mold Interfacial Heat Transfer during solidification in Graphite-Lined Author: Ashish Dhodare, P. Ravanan, Nimesh Dodiya. During Solidification in Casting A.

Dhodare Department of Production Engineering, Veermata Jijabai Technological Institute, Mumbai -India and heat transfer at metal mold interface is one of the important boundary condition to solve equation for solidification modelling in casting Author: Ashish Dhodare, P.

Ravanan, Nimesh Dodiya. Heat transfer between a solidifying casting and the mold is critical for achievement of high quality in the cast product. This is especially important in permanent mold casting where the rate limiting steps for heat transfer between the casting and the mold are primarily controlled by conditions at the mold-metal interface.

In the present work, the effect of superheat and chill thickness on the interfacial heat transfer during solidification of commercially pure aluminium has been investigated by estimating the heat flux transients and heat transfer coefficients at the casting/chill interface.

ExperimentalCited by: Interface Heat Transfer Coefficient between Casting and Round Chilled Moulds during Solidification of Aluminium Alloy Castings. S K Muttagi *, Dr. Geetanjali V Patil, Dr.

Suneelkumar N Kulkarni, nath Patil. Research Scholar*, Department of Mechanical Engineering Dr. BLDEA‟s College of Engineering Bijapur/ Professor Department of Mechanical Engineering Dr.

H Author: S K Muttagi, Geetanjali V Patil, Suneelkumar N Kulkarni, Vishwanath Patil. transfer at the gap increases with the size of the gap. The resistance to heat transfer at the interface will naturally be reflected in the solidification of the casting metal. It is thus very desirable to know the magnitude of this resistance to heat transfer, which is represented by an interfacial heat transfer.

If R is the radius of the inscribed sphere, the local solidification time t is proportional to R 2 /h where h is the heat transfer coefficient at the metal– mold interface. Thus at. The value of casting–mold interface heat transfer coefficient was determined during the alloy solidification and cooling processes based on temperature measurement in the casting and ceramic shell mold with the use of inverse method.

The calculations showed that its value varied during the solidification. The heat transfer mechanisms through the sand-casting interface were interpreted from an examination of the nature of the sand and casting surfaces. Heat transfer through the interface is proposed to occur by conduction through the gas forming the atmosphere of the interface and by radiation, in approximately equal amounts.

Modeling of casting solidification can provide a method for improving casting yields. An accurate casting solidification model might be used to predict microstructure and to control the process based on thermal and operational parameters, and for this, it is necessary the previous knowledge of the transient metal/mold heat transfer coefficient, h i.

During the casting process of green sand mold, air gaps will form between the metal and sand mold. The air gaps will make it difficult to analyze the heat transfer at the mold/metal interface.

Generally, an interfacial heat transfer coefficient is employed to evaluate the heat flux transferred across the air gaps.

Interfacial heat transfer coefficient at the metal-mold interface (IHTC) was estimated by an iterative algorithm based on the function specification method. An Al-9 wt% Si alloy plate casting was. For modeling solidification process of casting accurately, the correct information about the heat flux boundary condition is required.

In this study, an inverse heat conduction model is established to determine the interfacial heat flux at metal-mold in the process of casting with a cylindrical geometry. The numerically calculated temperature is compared with the exact solution and.

During centrifugal casting, the thermal resistance at the cast-mold interface represents a main blockage mechanism for heat transfer. In addition to the refractory coating, an air gap begins to form due to the shrinkage of the casting and the mold expansion, under the continuous influence of strong centrifugal forces.

Here, the heat transfer coefficient at the cast-mold interface h has been. metal is formed at the interface immediately after •Rate of freezing depends on heat transfer into mold, as well as thermal properties of the metal Figure -Shrinkage of a cylindrical casting during solidification and cooling: (0) starting level of molten metal immediately after.

This investigation focused primarily on the effect of surface roughness on heat transfer coefficient values whilst exploring the dynamics and mechanisms of heat transfer at the casting metal-mold interface during solidification of liquid metal.

Several experimental, computational and analytical techniques were developed and utilized. A cylindrical and horizontally oriented casting. Narayan Prabhu and John Campbell: “Investigation of Casting/Chill Interfacial Heat Transfer during Solidification of Al–11% Si Alloy by Inverse Modelling and Real-Time X-ray Imaging,” Int.

Cast Metals Res.,12, pp. – Keywords: Inverse heat conduction method, Casting/chill interface, Heat transfer coefficient, Heat flux With the rapid development of numerical simulation technology in the last two decades, the solidification simulation of casting has been taken as an effective tool for designing the casting process and improving the quality of casting1,2.

In the presence of an external heat flux, a heat flux equation for solidification becomes (11) q e = q + (T m / α) dq / dT where q e is the externally applied heat flux and q is the heat flux to be evaluated.

can be solved at the interface of solid and liquid, as shown in Fig. 1a, can be examined. In the cylindrical coordinates of r, ϕ, and z, as drawn in Fig.

1b, the heat flux q and the. events which govern heat transfer in the continuous casting process. The present work was undertaken to develop a fast, simple, and flexible model to investigate these heat transfer phenomena.

In particular, the model features a detailed treatment of the interfacial gap in the mold, which is the most important thermal resistance. The accurate estimation of heat transfer coefficients (HTC) at the metal-mold interface is essential to simulate casting solidification processes.

In this work, a 5-step casting mold was employed with section thicknesses of 2, 4, 8, 12, 20 mm. Wrought aluminum alloy was squeeze cast under an applied pressure of 60MPa in a hydraulic press.The effect of the interface pressure on the metal-chill Heat Transfer Coefficient (HTC) during the cooling of a A aluminum alloy in a gravity sand casting process is analyzed.In this paper, two dimensional numerical simulation of heat transfer during solidification of Al wt.

% Cu alloy cast in a cylindrical mold was carried out to specify the optimum solidification conditions. The mold has the dimensions of mm height, 38 mm outer radius, and 8 mm thickness.

Four cases were studied for the solidification process; first case is the solidification in the mold.