History of Ceramic Foam Filtration. (Aluminum Silver Anniversary Paper).
According to Mollard, there are a great deal of benefits to ceramic foam filtration in aluminum castings. These include a reduced scrap rate, increased yield, enhanced level and consistency of mechanical properties (primarily ductility, yield strength and fatigue resistance), and improved surface finish characteristics and machinability.
While initial applications of ceramic foam filters were for sand castings, they have now broadened to include permanent mold, plaster and ceramic investment castings. Other casting benefits include:
* several reliable commercial suppliers;
* conductivity with all major aluminum casting alloys;
* ability to perform in-mold filtration in combination with filtered primary ingots, as well as crucible formation, to achieve optimum cleanliness and mechanical properties;
* current availability at ceramic foam compositions including a variety of refractory aggregate/bonding materials tailored to consumer specifications;
* the replacement of early chromite bonded ceramic foams by environmentally benign and stronger refractory compositions.
Mollard also sees many possible future markets for ceramic foam filters, including diecasting and semi-solid casting. The use of computer-aided analysis of aluminum flow could lead to inclusion retention to optimize filter porosity, shape, size and placement.
"The technology for producing clean aluminum castings through ceramic foam filtration has considerably matured since its initial introduction in the 1970s," Mollard said. "This progress is attributable to the sustained efforts of many individuals and organizations and an interdisciplinary approach involving primarily foundry metallurgists and ceramic engineers."
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|Comment:||History of Ceramic Foam Filtration. (Aluminum Silver Anniversary Paper).|
|Article Type:||Brief Article|
|Date:||Jun 1, 2003|
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