Measuring the interfacial heat transfer coefficient between flowing molten alloy and sand mold using fluidity tests

This study specifically examined a method using fluidity test results to measure the interfacial heat transfer coefficient (IHTC) between a molten alloy and a mold during flow. Review of earlier studies revealed that conventional methods require the choking area length to calculate the IHTC during flow, but one earlier study used an assumed choking area length. Details of its length remain unclear. Using an arbitrarily chosen choking area length leads to inaccurate acquisition of the IHTC. For this study, we observed the microstructures and macrostructures around a fluidity test specimen tip to ascertain the choking area length. This value led to calculation of the IHTC between the flowing bronze melt and the shell sand mold as 1521 W/m²•K. This study also found a new method requiring no choking area length to ascertain the IHTC between the flowing melt and the sand mold. The IHTC obtained using this method was 1406 W/m²•K, representing a difference of about 8% from the value obtained using a conventional method. This study assessed experimental conditions under which the new method can produce accurate IHTC values.