Thermal Model for the Fluidity of Metals in Casting

The fluidity of a cooling liquid metal is calculated using a slug flow model in which metal in the freezing range flows as a mixture of liquid and solid, and freezing is assumed to occur first at the face of the slug. Comparison is made with an alternative model in which solid metal is assumed to be deposited continuously on the mould wall. Application of the theory to the solidification of an iron-carbon alloy indicates results at variance with experiments on sand casting. It is concluded that mathematical analysis of the fluidity of binary alloys which incorporates heat transfer effects alone is inadequate to describe solidification during flow. This conclusion is not necessarily true for pure metals and eutectic alloys, nor for the solidification of binary alloys under pressure die casting conditions.