1. Modeling Direct Chill Casting of Aluminum Alloys Cathryn Karashin Advisor: Dr. Krane

2. 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

3. Direct Chill Casting Direct chill (DC) casting process is used for 68% of the aluminum ingots processed in the US 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

4. DC Casting: Mold and Ingot Photos courtesy of M. Krane

5. Sump Depth Sump depth at start up? Flood et al. believe the sump 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

6. 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 generate graphs and analyze data Photo courtesy of http://www.gre.ac.uk/~physica

7. Project Objectives To model heat transfer and solidification phenomena in direct chill casting using Physica software To study sump shapes during start up as basis for future stress analysis

8. Progress of Models 1 st Model: pure Al, simple cooling using fixed values 2 nd Model: pure Al, simple cooling using fixed values, solidification 3 rd Model: Al-Cu 5%, cooling using heat transfer coefficient, solidification

9. 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

10. Wedge to Cube

11. 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

12. Cube Simulations Cooling from sides and bottom Notice liquid center (red) and solidified region (blue)

13. Cube Simulations Cooling from side only Notice liquid center (red) and solidified region (blue) Note large different between this and previous plot

14. Resultant Velocity at 20s

15. Liquid Fraction at 400s

16. Thanks to: Dr. Krane All the grad students that have helped me when I’m stuck in the lab Purdue