In their presentation, "Folds Formation and Prevention in the Lost Foam Aluminum Process" (04-080) Q. Zhao, Metal Casting Technology Inc., T.W. Gustafson and M. Hoover, General Motors Powertrain, and M.C. Flemings, Massachusetts Institute of Technology, discussed the fundamentals of lost foam aluminum casting, including various types of process-specific defects that were collected from both production and research environments to characterize and understand defect formation principles.
Visual inspection (both real time and post cast) and surface analysis indicated that all the defects analyzed, despite differences in shape, size, color and occurrence, have similar surface structures and share the same root cause in defect formation, it is the variation in fold formation path within and among castings that leads to an apparent complexity in defect appearance.
Also presented during the sessions was an AFS Research Report, "Comparison of Aluminum Alloys and EPS Foams for Use in the Lost Foam Casting Process" (04-110).
Author D. Hess, General Motors Powertrain, examined aluminum alloys 319, 356 and 206 for use in lost foam. His findings showed that alloy 206 has similar castability, to alloys 319 and 356. In fact, metal front velocities and total defect area were found to be slightly higher for alloy 206.
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|Title Annotation:||108th Metalcasting Congress Report|
|Article Type:||Brief Article|
|Date:||Jul 1, 2004|