MEASUREMENTS OF METAL-MOLD INTERFACIAL HEAT TRANSFER COEFFICIENTS DURING SOLIDIFICATION OF Sn AND Sn-Pb ALLOYS
- 1 April 1993
- journal article
- research article
- Published by Informa UK Limited in Experimental Heat Transfer
- Vol. 6 (2), 111-129
- https://doi.org/10.1080/08916159308946449
Abstract
A study is reported on the evolution of the thermal resistance at the interface between the mold and the metal during soiidi/ication of metal castings. Experiments were performed to measure the interfacial heat transfer coefficient (hI) for solidification of Sn and Sn-Pb alloys from a vertical wall. The experiments with pure Sn were simulated numerically using a constant hI and good agreement was found. The variation of hI in the presence of a mushy zone at the interface was studied. In the case of a Sn-10wt%Pb alloy it was found that hI varied as a function of the liquid fraction at the interface. The interfacial heal transfer coefficient had a higher value during the initial stage of solidification, when the liquid fraction at the interface was high. However, as the temperature at the interface approached the eutectic temperature and the liquid fraction decreased to zero, ft, dropped to a lower value. Once the temperature at the interface fell below the eutectic temperature, hI, remained approximately constant. In the case of a eutectic Sn-Pb alloy, the interfacial resistance increased slightly due to thermal contraction of the metal as solidification proceeded. The observed variation in hI, for the three different metals examined in this study is explained by volumetric contraction upon solidification.Keywords
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