Abstract
Fluidity tests for semi solid processed grey cast iron were conducted at different degrees of primary fraction solid using fluidity strips with 2·5, 5 and 14 mm wall thickness. The microstructure of the fluidity strip castings was examined. Fluidity parameters, such as slurry velocity, critical solid concentration and choking range were studied. It can be concluded that critical solid concentration increases with the increase of wall thickness. The slurry velocity drops suddenly at a certain fraction solid very near to the critical solid concentration. Choking range zone can be measured by observing microstructure. A solidification model for fluidity has been developed based on the literature and microstructure study of semi solid processed grey cast iron. A mathematical equation has been obtained from the solidification model by modifying Flemings' fluidity model in order to analyse cavity filling of semi solid grey cast iron.