Modeling of eutectic macrosegregation in centrifugal casting of thin walled ZA8 zinc alloy

The maximum segregation zone and microstructure formation during the solidification of thin walled ZA8 zinc–aluminum alloy produced by centrifugal casting are investigated. From the results obtained, it is seen that the maximum segregation zone of the eutectic through the part section corresponds to the zone of final solidification point. The concentration of eutectic through the section changes depending on the initial mold temperature, pouring temperature, and cooling rate. A high cooling rate reduces the rate of change in eutectic concentration across the section. The distance separating the maximum segregation zone from the inner and outer faces of the casting can be controlled by controlling the ratio between the speeds of the solidification fronts advancing from opposite sides. The microstructure obtained becomes finer as the cooling rate increases. The structure of eutectic changes according to the cooling rate, and may be granular or lamellar.