Testing for Thermal Distortion in Chemically-Bonded Foundry Sands

The automotive/metalcasting industry has realized the need for near-net shape casting. Powertrain components are designed to assuage in close tolerance. A goal of the foundry engineer is to produce cores and molds of consistent dimensional accuracy, and hence a casting satisfying the ever tighter tolerances of the automotive industry. The developers and users of chemical binders, in hot or cold box cores or on patterns for mold, all have this issue in mind.

A thermal distortion tester, developed at Western Michigan University for examining the thermomechanical properties of chemically-bonded sands, is described. It is simple to operate and the test piece is a “disc transverse strength specimen” used with chemically-bonded sands.

The tester can be used for process control to establish a materials control program and for dimensional control of cores and molds. The tester is another tool that would aid in identifying correct amounts of binder materials and catalysts, and for predicting the behavior of the core and mold material in thermo-mechanical application. The thermal distortion curves of sand/binder systems are discussed.