A foundry-based experimental investigation into the effect of die coats in the gravity casting process

Abstract

An experimental investigation into air gap development and heat transfer at the casting-die interface is described. The experiments were carried out on a shaped casting under foundry conditions and the effect of different die coat thicknesses was investigated. The experiments show the complex mechanical contractions which take place, the restraining/supportive effect of the tooling and its effect on heat transfer. The die coat is seen to be most influential in reducing heat loss early in the transient, the heat-transfer coefficient being independent of die coat thickness on development of the air gap. These trends are similar to those encountered in laboratory experiments, although for this shaped casting the heat-transfer coefficients in the early phase are notably larger.