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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