Creating a Thermal Property Database for Investment Casting Shells


 Surface topology is used to calculate the effective thicknesss of the test specimen.

Surface topology is used to calculate the effective thicknesss of the test specimen.

Reliable and realistic thermal properties data for investment casting shell molds are required to correctly simulate the metal solidification and predict the shrinkage. Investment casting shells exhibit several phase transformations during firing and pouring that affect their transient thermal properties which affect solidification. These properties depend on time, temperature and process history.
A recent study collected thermal conductivity and specific heat capacity data from seven industrially produced ceramic molds of various types using an inverse method in which pure nitrogen was poured into ceramic molds equipped with two thermocouples. Software was used to simulate virtual cooling curves that were fitted to experimental curves by adjusting the temperature-dependent properties of the ceramic mold. The data were compared with measurement results from laser flash. The analysis of the differences will serve to improve the accuracy of investment casting simulation.

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