Measurement of Exothermic Values of Casting-sleeve Materials Using an Ice Calorimeter

Abstract

Defects, which are a major problem in casting, can affect the integrity of products. The processes used to reduce defects are often complex and increase manufacturing cost. Simulations are used to predict casting defects by analyzing the flow and solidification of the metal. However, simulation results often differ from actual casting results because appropriate values for the physical properties have not yet been experimentally obtained. Thus, in this study, an ice calorimeter was developed to measure the exothermic value of sleeve materials under rapid heating conditions. In the case where a thermocouple or radiation thermometer is used to determine the heater temperature, heat loss due to the lead wires or hole for temperature measurement cannot be avoided. Therefore, in this study, the heater resistance was obtained using current and voltage, and the temperature was determined using the resistance value. Although some variations were observed, the average measured exothermic values of all exothermic sleeve materials (1.2 kJ/g) matched approximately with those predicted by computer simulation using known thermophysical properties and experimentally obtained distributions of shrinkage cavities. Therefore, the exothermic values obtained in this study are considered valid.