Abstract
A finite-element model has been developed to predict the evolution of temperature, stress, and shape of 10-mm diameter molten steel droplets solidifying against a water-cooled copper chill plate. The elastic-viscoplastic stress model accounts for thermal linear expansion / contraction behavior, creep, and phase transformations that vary with carbon content. Thermal contraction causes the quenched surface of the impinged droplet to bend away from the chill plate. This creates interfacial resistance that greatly lowers heat transfer. The droplet shape is predicted to evolve almost entirely during the first 0.1 second, when a thin solid skin first forms and becomes strong enough to contract. The final shape of the droplet interface predicted by the model agrees both qualitatively and quantitatively with previous measurements reported by Dong and coworkers. The most deformation, as indicated by the final curvature of solidified droplets, is found in high purity iron (0.003%C) and in peritectic steels (0.12%C). This deformation can be reduced by lowering heat transfer coefficient and avoiding sudden large drops in h. Large drops in heat transfer coefficient also cause reheating of the droplet surface, despite the neglect of nonequilibrium undercooling effects in the model. It is important to minimize surface roughness during initial solidification in order to avoid non-uniform solidification, which is responsible for many casting defects.
Original language | English (US) |
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Pages | 509-520 |
Number of pages | 12 |
State | Published - 1998 |
Event | Proceedings of the 1998 TMS Annual Meeting - San Antonio, TX, USA Duration: Feb 15 1998 → Feb 19 1998 |
Other
Other | Proceedings of the 1998 TMS Annual Meeting |
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City | San Antonio, TX, USA |
Period | 2/15/98 → 2/19/98 |
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys