Relation between SDAS and eutectic cell size in grey iron

The solidification of cast components is a complex and important process as this is the moment when the final properties are established. For hypoeutectic grey iron, solidification starts with nucleation and growth of the primary austenite followed by the eutectic reaction forming eutectic cells. In this work, the microstructure and significance of the different constituents formed during solidification has been examined. It was found that the size of the eutectic cells is a function of secondary dendrite arm spacing (SDAS). The SDAS, on the other hand, was found to depend on the solidification time and hence the growth rate of the dendrites. The effect of chemical composition on SDAS and eutectic cell size was found to depend on cooling rate. It is suggested that the relationship between the eutectic cells and dendrite arm spacing is based on segregation effects and the nucleating capacity of the melt.