Triple Junction Analysis
Thermal analysis was performed on web sections from bond- ed olivine sand and pre-heated ceramic shell molds cast by industrial foundries to predict location of shrinkage porosity.
Conclusions
Solidification modeling provides strong guidelines when casting lightweight, high aluminum steel with complex mold shapes. Pre-heated (800°C) ceramic shell molds pro- duce less porous P900 plates than bonded-sand molds, an absence of cold shuts, and no evidence of hot cracking or tearing. Cold shuts can be prevented in 15° tilted bonded sand molds with a combination of venting along the back of the mold and a superheat of 300°C.
Acknowledgements
I would like to acknowledge Dr. Simon Lekakh for all of his help with FLUENT modeling.
BIBLIOGRAPHY
1. Howell, R.A., Montgomery, J. S., and Van Aken, D.C., “Advancements in Steel for Weight Reduction of P900 Armor Plate,” AIST Trans. 6 (5), pp. 168-176 (2009).
2. Howell, R.A., and Van Aken, D.C., “A Literature Review of Age Hardening Fe-Mn-Al-C Alloys,” AIST Trans. 6 (3), pp. 193-212 (2009).
3. Heine, R.W., Loper, C.R. Jr., Rosenthal, P.C., Principles of Metal Casting, McGraw-Hill Book Company, 2nd edition, pp 96-99 (1967)
4. Howell, R.A., Lekakh, S.N., Van Aken D.C., Richards, V.L., “The Effect of Silicon Content on the Fluidity and Microstructure of Fe-Mn-Al-C Alloys,” AFS Transactions, vol. 116, pp 867-878 (2008)
5. Howell, R.A., Weerasooriya, T. and Van Aken, D.C., “Tensile, High Strain Rate Compression and Microstructural Evaluation of Lightweight Age Hardenable Cast Fe-30Mn-9Al-XSi-0.9C-0.5Mo Steel,” AFS Trans. 117, pp. 751-763 (2009).
INTERCHANGEABLE MOONBUGGY WHEELHUBS K. Launchbaugh
Pittsburg State University, Pittsburg, KS, USA Copyright © 2010 American Foundry Society Introduction
The basis for my project was a development of a larger Senior Design project, The Great Moonbuggy Race. This event is held every year in Huntsville, Alabama at the NASA Space & Rocket Center; it’s a series of various lunar-like obstacles over the course of seven tenths of a mile. The race is a gathering of students from all across the US, Canada, Germany, India, Mexico, and Romania. The event requires the competitors to design their vehicle according to specific criteria, build, and then race their human powered vehicle.
Design
Upon beginning the designing of our vehicle we decided upon a few key features for it, one of which was the need for a hub that would be light-weight, strong, and function for both the front and rear axles; this was how my individ- ual project began. The basis of the hub was that it would be secured by three points on the rear suspension setup, with two mounting points on the front while the third point would serve as the steering attachment point.
International Journal of Metalcasting/Winter 10
This project would present a terrific chance for me to utilize my metalcasting design knowledge. After calcu- lations were figured I found that the load to be put upon the wheels and suspension system could be feasibly sup- ported by using aluminum castings for the hubs. A356 Aluminum was chosen for the material because it was heat-treatable, machines well, and we also had A356 Aluminum bars on-hand so the convenience of it was a factor too.
Once the initial forces, to be placed upon the hub, were determined I begin to do the actual designing of the part itself. All of our design work was done utilizing Pro-E, fol- lowing the dimensional construction of the part in Pro-E, I utilized the Mechanica software package for Pro-E to do the appropriate Static Load testing simulation. After apply- ing force loads I found that the part was more than strong enough and so material section thickness reduction was naturally the next step. After slimming the part profile from 9.2 cubic inches to 4.5 cubic inches I was satisfied with the physical structure of the hub and begin working on the gating system.
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