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Modeling Direct Chill Casting ofAluminum Alloys

Cathryn Karashin

Advisor: Dr. Krane

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Aluminum Applications

Beverage cans, planes,

trains, automobiles,boats, spacecraft parts

Used as the mold

material in Al casting

Al is very lightweight (1/3

the weight of steel) so it

is very useful

Picture courtesy of Aluminum: Technology, Applications, and

Environment by Dietrich G. Altenpohl

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Direct Chill Casting

Direct chill (DC) casting process is used for

68% of the aluminum ingots processed in theUS

Ingot scrap from stress cracks and butt

deformation account for a 5% loss in

production

Control of scrap levels is important both in

terms of energy usage and cost savings

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DC Casting: Mold and Ingot

Photos courtesy of M. Krane

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Sump Depth

Sump depth at start up?

Flood et al. believe thesump increases at start

up, then decreases and

plateaus

Through modeling, we

hope to have a more

definite answer

A scaling Analysis for the Heat Flow, Solidification &

Convection in Continuous Casting of Aluminum by Flood,

Davidson, & Rogers

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Physica Version 2.11

Models thermal and

mechanical properties

Puts continuous equations

into discrete parts; breaking

down into simple algebraic

terms

Produces a results file that

can be used to generategraphs and analyze data

Photo courtesy of http://www.gre.ac.uk/~physica

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Project Objectives

To model heat transfer and solidification

phenomena in direct chill casting using Physicasoftware

To study sump shapes during start up as basis

for future stress analysis

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Progress of Models

1st Model: pure Al, simple cooling using fixed

values 2nd Model: pure Al, simple cooling using fixed

values, solidification

3rd Model: Al-Cu 5%, cooling using heat

transfer coefficient, solidification

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Wedge Gone Bad

Started using

simulations with a wedge Axisymmetric properties

of wedge made it ideal

Problem with geometry

of translating smaller

wedge to larger wedge

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Wedge to Cube

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Simulations with the Cube

pure Al, simple cooling using fixed values,

solidification Pure Al, simple cooling using fixed values,

solidification, fluid flow

Pure Al, simple cooling using fixed values from

only side mold wall, solidification, fluid flow

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Cube Simulations

Cooling from sides and

bottom Notice liquid center (red)

and solidified region

(blue)

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Cube Simulations

Cooling from side only

Notice liquid center (red)and solidified region

(blue)

Note large different

between this and

previous plot

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Resultant Velocity at 20s

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Liquid Fraction at 400s

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Thanks to:

Dr. Krane

All the grad students that have helped mewhen Im stuck in the lab

Purdue