Mathematical Modeling of Copper and Brass Upcasting

A study has been performed to establish basic knowledge in heat transfer and solidification for copper and brass upcasting. The study combined pilot scale measurements, mathematical modeling, and metallographic examination of lhe cast rod samples. The pilot scale measurements involved temperature measurements with several thermocouples inserted in the copper jacket of the mold. Temperature measurements of the surface of the cast rod were carried out as well. A three-dimensional (3-D) mathematical model of the copper mold and graphite die was constructed to characterize the heat flux profiles quantilatively from the measured mold temperature data. The heat flux was observed to have a maximum value near the first contact point between the copper mold and the graphite die and to decrease rapidly with increasing distance up to the mold. The calculated heat flux profiles were used as boundary conditions for another mathematical model, which calculated temperature profiles in the cast rod. A model for estimation of material data and microstructure was used for simulating the thermophysical data needed in the calculations and to predict certain microstructural properties in the cast rods. The calculated surface temperatures of the cast rod at the mold exit agreed well with the measured temperature values. Also, the calculated microstructural properties, such as secondary dendrite arm spacing, phase distribution, and microsegregation of zinc, were in good agreement with the measured ones.