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Benchmark testing using experimental data for mold filling and solidification modeling of high-density alloy gravity die castings
Surghani, Nadira E.
Surghani, Nadira E.
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2024
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2025-11-26
Abstract
Casting modeling is a complex yet powerful computational tool that has the potential to increase the yield and quality of cast parts. Gravity die castings (GDC) are difficult to model due to the simultaneous occurrence of fluid flow, heat transfer, and phase change. The casting conditions and parameters set by the foundry workers are dependent on the complex physical phenomena and ultimately have a coupled effect on the final cast product. The simultaneous physics has made experimental validation difficult as well, particularly concerning mold filling where heat transfer, fluid flow, and phase change are all combined. In this study, proton radiography (pRad) is used as a novel technique to gather in situ images of molten metal during mold filling. pRad images, thermophysical properties from the literature, instrumented thermocouple data during casting, and quantified microstructure from experimental castings are all used to build and validate two GDC of high-density metallic materials. The models were built using a computational fluid dynamics (CFD) software known as FLOW-3D®.
Metal-mold heat transfer coefficients (HTC) used in previous studies were merely an approximation, but now using novel pRad data it is recommended that the metal-mold HTC values are higher than previously considered, likely between 103 and 104 W/m2/C. pRad imaging paired with thermocouple data has enabled the model validation of coupled phenomenon occurring during mold filling. In addition to fluid flow, the model can adequately track temperature evolutions in the melt and mold that can be linked to as-cast microstructure development, proper directional solidification, and foresee the formation of potential defects like shrinkage porosity. Finer spatial details were more difficult to replicate in the model, especially at the mold/metal and metal/air interfaces. This could be linked to the boundary conditions and interfacial heat transfer that are difficult to experimentally measure and ultimately model. These novel experiments combined with modeling/simulation will provide the pathway in the prediction and control of casting quality and advanced manufacturing of metals and alloys.
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