LAUSR

Centrifugal investment casting is an attractive method of producing orthopedic implants. This study investigated the effects of low rotational speed of vertical centrifugal investment casting on the microstructural characteristics, porosities and hardness of a titanium femoral knee. The centrifugal investment casting was conducted at 45-65 rpm. The microstructure, defects and microhardness of titanium resulting from centrifugal investment casting were discussed. Experimental results showed that centrifugal casting at a rotational speed of 45-65 rpm could obtain the casting without damaging the surface. The largest inner defect was typically the shrinkage because of the solidification process beneath the smallest parts. The microstructure transformed from a fine grain on the subsurface to a slightly coarse one in the inner region. Microhardness profiles on the cross section presented a decreasing tendency from the surface to the inner region because of the shift of the microstructure.