Relationship between Casting Distortion, Mold Filling and Interfacial Heat Transfer in Sand Molds
The objective of this project is to determine the effect of interfacial heat transfer coefficients and gap formation in iron and aluminum sand mold castings on casting dimensional accuracy.
An experiment was designed which requires pouring more than 300 castings to compare dimensional fidelity between different castings. A non-contact method for determining when a gap forms between a solidifying casting and the mold was developed. The procedures for measuring the heat transfer coefficient have been developed.
The statistical analysis of casting dimensions confirms that orientation, gating, and section thickness do indeed affect casting dimensional accuracy. The evidence from heat transfer measurements indicates that no reproducible gap forms in aluminum alloys poured in sand molds. Our values for interfacial heat transfer coefficients show that they are a function of the section thickness. Of perhaps more importance, we have isolated the error effect of thermocouples in making temperature measurements. In thin sections, they are significant.