A Study of the Heat Transfer Behavior of Mold Fluxes with Different Amounts of Al2O3
Abstract
:1. Introduction
2. Materials and Methods
2.1. Experimental Slags
2.2. The Heat Transfer Test
2.3. The Initial Crystallization Temperature Test
2.4. Phase Analysis
3. Results and Discussion
3.1. The Heat Transfer Procedure
3.2. The Effect of Al2O3 Content on Heat Flux
3.3. The Effect of Al2O3 Content on Interface Thermal Resistance
4. Conclusions
- The final steady-state heat flux of Sample R0.8A7 (Al2O3, 7%) was 423 kW·m−2, while it decreased to 419 kW·m−2 (Sample R0.8A20) and then to 372 kW·m−2 (Sample R0.8A30) when the Al2O3 content increased from 7% to 20% and then to 30%, respectively; however, it increased to 383 kW·m−2 as the Al2O3 content was continuously increased to 40%.
- Both crystalline layer thickness and fraction increased first, then decreased with the further addition of Al2O3. Additionally, it was the mold flux crystallization, together with the resulted interfacial thermal resistance, that dominated the heat transfer performance of the mold flux—not the specific precipitated crystal phase.
- The Rint increased from 9.2 × 10−4 m2·kW−1 (Sample R0.8A7) to 11.0 × 10−4 m2·kW−1 (Sample R0.8A20) and then to 16.0 × 10−4 m2·kW−1 (Sample R0.8A30) when the addition of Al2O3 content increased from 7% to 20% and then to 30%, respectively; however, it decreased to 13.6 × 10−4 m2·kW−1 (Sample R0.8A40) when the Al2O3 content reached 40%.
- The variation in the interfacial thermal resistance Rint was proportional to crystalline fraction of the mold fluxes, as the interface thermal resistance was mainly caused by the deformation and shrinkage of the mold flux during its crystallization process.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Sample | CaO | SiO2 | Al2O3 | MgO | F− | Na2O | Li2O | R |
---|---|---|---|---|---|---|---|---|
R0.8A7 | 33.53 | 42.05 | 7.02 | 2.00 | 5.88 | 9.02 | 0.50 | 0.8 |
R0.8A20 | 27.84 | 34.70 | 20.01 | 2.02 | 5.91 | 9.02 | 0.50 | 0.8 |
R0.8A30 | 23.37 | 29.16 | 30.01 | 2.01 | 5.94 | 9.01 | 0.50 | 0.8 |
R0.8A40 | 18.89 | 23.60 | 40.00 | 2.00 | 5.98 | 9.01 | 0.50 | 0.8 |
Al2O3 Cont. | Tg/c (°C) | Tms (°C) | dcrystalline (mm) | dglassy (mm) |
---|---|---|---|---|
7% | 830 | 103 | 2.30 | 1.00 |
20% | 816 | 100 | 2.51 | 0.79 |
30% | 791 | 96 | 2.96 | 0.34 |
40% | 803 | 97 | 2.68 | 0.62 |
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Zhou, L.; Wang, W.; Zhou, K. A Study of the Heat Transfer Behavior of Mold Fluxes with Different Amounts of Al2O3. Metals 2016, 6, 139. https://doi.org/10.3390/met6060139
Zhou L, Wang W, Zhou K. A Study of the Heat Transfer Behavior of Mold Fluxes with Different Amounts of Al2O3. Metals. 2016; 6(6):139. https://doi.org/10.3390/met6060139
Chicago/Turabian StyleZhou, Lejun, Wanlin Wang, and Kechao Zhou. 2016. "A Study of the Heat Transfer Behavior of Mold Fluxes with Different Amounts of Al2O3" Metals 6, no. 6: 139. https://doi.org/10.3390/met6060139