An Instrumented Uranium Hemispherical Casting

Abstract

This work describes an instrumented uranium casting experiment and the analysis of the results. The casting is a hemisphere with inner radius of 75 mm and wall thickness of 10 mm. Casting was performed in a multi-coil vacuum induction melting (VIM) furnace with separate induction power supplies for each coil. One coil was used to heat the crucible and melt the charge material. The second coil was used to heat the top of the mold in order to preheat the mold and obtain the desired initial mold temperature. The current, voltage, and frequency of the mold coil was measured during mold heating. The mold filling rate was measured by a load cell was placed under the mold stack. The thermal history of the casting was measured by 7 thermocouples in the casting cavity and 22 thermocouples imbedded in the graphite mold. Contact pins were also located in the mold to attempt to measure gap formation in the metal-mold interface. This instrumentation provides an in-depth thermal history of the mold heat-up, mold filling, solidification, and cool down. The thermocouples were positioned to allow for the casting/mold interfacial heat transfer coefficient to be determined as a function of position and time. The casting was sectioned and metallography and chemical analysis was performed.