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Centrifugal casting is the
process of applying centrifugal force to liquid metal (using a spinning
mold), whereupon it solidifies into a dense, sound casting. As metal
solidifies in a stationary casting, it undergoes a reduction in volume
known as "shrinkage." Shrinkage occurs when the metal on the outside wall
of the casting solidifies and "draws" the inside metal toward it until
solidification is complete. This "Drawing of metal" leaves cavities which
reduce the mechanical properties of the casting.
By applying centrifugal force to the metal as it solidifies, shrinkage can
be minimized. As the metal solidifies on the outside wall of the casting,
the centrifugal force feeds the inside metal, producing a uniform
directional solidification.
The centrifugal casting process involves four necessary operations. These
operations include rotation of mold at a predetermined speed, pouring the
molten metal, establishment of a proper in-mold solidification rate, and
extraction of the casting from the mold.
The purpose of this experiment was to study the effect of rotation speed
on casting wall thickness during centrifugal casting. This was observed by
pouring four aluminum alloy castings using a centrifugal casting machine
constructed at the university.
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