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ArticleName Determination of heat transfer coefficient between AZ91 magnesium alloy casting and no-bake mold
DOI 10.17580/tsm.2017.08.14
ArticleAuthor Bazhenov V. E., Petrova A. V., Koltygin A. V., Tselovalnik Yu. V.

National University of Science and Technologies “MISiS”, Moscow, Russia:

V. E. Bazhenov, Senior Lecturer of a Foundry Technologies and Material Art Working Department, e-mail:
A. V. Petrova, Master's Student of a Foundry Technologies and Art Working Department
A. V. Koltygin, Assistant Professor of a Foundry Technologies and Material Art Working Department
Yu. V. Tselovalnik, Master's Student of a Foundry Technologies and Material Art Working Department


It is necessary to know the interface heat transfer coefficient (iHTC) between the casting and the mold for the simulation of casting filling and solidification processes in the casting simulation software systems. This study demonstrates the way we determined the heat transfer coefficient h between the cylindrical casting of 50–56 mm in diameter and 150 mm in height of the AZ91 magnesium alloy and no-bake mold on synthetic resin binder. The temperature field in the mold and the temperature of the alloy were determined using twelve thermocouples installed in the mold and mold cavity. Their temperature data were recorded when pouring, solidification and cooling of the casting. The ProCast software used for the simulation of filling and solidification of castings. Then the cooling curves were obtained for the points in the model corresponding to the position of thermocouples during the experimental casting. We used the thermal properties of the mold available in the literature and the thermal properties of the alloy calculated using the ProCast thermodynamic database. Simulation and recording of temperature measurements were carried out to 1500 s. To determine the heat transfer coefficient the error function was used. It indicates the difference between the experimental and calculated values of the temperature in the casting and mold. The value of heat transfer coefficient was set as temperature dependence. The value of the heat transfer coefficient in the range hL = 600–1300 W/(m2·K) in every 100 W/(m2·K) was set above the liquidus temperature (610 оC) of the alloy. The heat transfer coefficient hS = 500–700 W/(m2·K) was set below the solidus temperature of the alloy (415 оC). We tried to find a value of heat transfer coefficient at which the error function was minimized, and hence the difference between the calculated and experimental temperature field in the casting and mold has also been minimal. The obtained values of the heat transfer coefficient between the casting and mold are hL = 1100 W/(m2·K) above the liquidus temperature and hS = 600 W/(m2·K) below the solidus temperature. Such heat transfer coefficient values give the error function not more than 20 оC.

This work was carried out with the support of the Russian Federation President's Grant to the young scientists and post-graduate students, carrying out the prospective scientific investigations and developments on priority ways of modernization of russian economics (contest of 2016–2018).

keywords Computer simulation of foundry processes, ProCast, interface heat transfer coefficient, iHTC, no-bake, sand casting, thermal properties, magnesium alloy AZ91.

1. Wang D., Zhou C., Xu G., Huaiyuan A. Heat transfer behavior of top side-pouring twin-roll casting. Journal of Materials Processing Technology. 2014. Vol. 214. pp. 1275–1284.
2. Griffiths W. D., Kawai K. The effect of increased pressure on interfacial heat transfer in the aluminium gravity die casting process. Journal of Materials Science. 2010. Vol. 45, No. 9. pp. 2330–2339.
3. Sun Z., Hu H., Niu X. Determination of heat transfer coefficients by extrapolation and numerical inverse methods in squeeze casting of magnesium alloy AM60. Journal of Materials Processing Technology. 2011. Vol. 211. pp. 1432–1440.
4. Nishida Y., Droste W., Engler S. The Air-gap formation process at the casting-mold interface and the heat transfer mechanism through the gap. Metallurgical Transactions B. 1986. Vol. 17B. pp. 833–844.
5. Tikhomirov M. D. Simulation of thermal and shrinkage processes during the solidification of high-strength aluminium castings and development of casting technology computer analysis system : thesis of Inauguration of Dissertation … of Candidate of Engineering Sciences. Saint Petersburg : SPbGPU, 2004.
6. Bouchard D., Leboeuf S., Nadeau J. P., Guthrie R. I. L., Isac M. Dynamic wetting and heat transfer at the initiation of aluminum solidification on copper substrates. Journal of Materials Science. 2009. Vol. 44, No. 8. pp. 1923–1933.
7. Lu S.-L., Xiao F.-R., Zhang S.-J., Mao Y.-W., Liao B. Simulation study on the centrifugal casting wet-type cylinder liner based on ProCAST. Applied Thermal Engineering. 2014. Vol. 73. pp. 512–521.
8. Chen L., Wang Y., Peng L., Fu P., Jiang H. Study on the interfacial heat transfer coefficient between AZ91D magnesium alloy and silica sand. Experimental Thermal and Fluid Science. 2014. Vol. 54. pp. 196–203.
9. Sutaria M., Gada V. H., Sharma A., Ravi B. Computation of feed-paths for casting solidification using level-set-method. Journal of Materials Processing Technology. 2012. Vol. 212. pp. 1236–1249.
10. Baghani A., Davami P., Varahram N., Shabani M. O. Investigation on the effect of mold constraints and cooling rate on residual stress during the sandcasting process of 1086 steel by employing a thermomechanical model. Metallurgical and Materials Transactions: B. 2014. Vol. 45. pp. 1157–1169.
11. Palumbo G., Piglionico V., Piccininni A., Guglielmi P., Sorgente D., Tricarico L. Determination of interfacial heat transfer coefficients in a sand mould casting process using an optimised inverse analysis. Applied Thermal Engineering. 2015. Vol. 78. pp. 682–694.
12. Bertelli F., Cheung N., Garcia A. Inward solidification of cylinders: Reversal in the growth rate and microstructure evolution. Applied Thermal Engineering. 2013. Vol. 61. pp. 577–582.
13. Martorano M. A., Capocchi J. D. T. Heat transfer coefficient at the metalmould interface in the unidirectional solidification of Cu – 8%Sn alloys. International Journal of Heat and Mass Transfer. 2000. Vol. 43. pp. 2541–2552.
14. Griffiths W. D. A model of the interfacial heat-transfer coefficient during unidirectional solidification of an aluminum alloy. Metallurgical and Materials Transactions: B. 2000. Vol. 31B, No. 2. pp. 285–295.
15. State Standard GOST 2138–91. Moulding sands. General specifications. Introduced: 1993–01–01.
16. Scheil E. Remarks on the crystal layer formation. Metallkd. 1942. Vol. 34. pp. 70–72.
17. Chandler H. Heat treater’s guide: practices and procedures for nonferrous alloys. OH : ASM International, 1996. 669 р.
18. State Standard GOST 2856–79. Casting magnesium alloys. Grades. Introduced: 1981–01–01.
19. Rudajevová A., Stank M., Luká P. Determination of thermal diffusivity and thermal conductivity of Mg – Al alloys. Materials Science and Engineering: A. 2003. Vol. 341, No. 1. pp. 152–157.
20. Lee S., Ham H. J., Kwon S. Y., Kim S. W., Suh C. M. Thermal conductivity of magnesium alloys in the temperature range from –125 оC to 400 оC. International Journal of Thermophysics. 2013. Vol. 34, No. 12. pp. 2343–2350.
21. Rudajevová A., Kiehn J., Kainer K. U., Mordike B. L., Lukác P. Thermal diffusivity of short-fibre reinforced Mg – Al – Zn – Mn alloy. Scripta materialia. 1998. Vol. 40, No. 1. pp. 57–62.
22. Rudajevová A., Luká P. Thermal diffusivity and thermal conductivity of Mg alloys and Mg-matrix composites. Acta Universitatis Carolinae. Mathematica et Physica. 2000. Vol. 41, No. 1. pp. 3–36.
23. Lindemann A., Schmidt J., Todte M., Zeuner T. Thermal analytical investigations of the magnesium alloys AM 60 and AZ 91 including the melting range. Thermochimica acta. 2002. Vol. 382, No. 1. pp. 269–275.
24. Babichev A. P., Babushkina N. A., Bratkovskiy A. M. et al. Physical quantities : reference book. Ed.: I. S. Grigorev, E. Z. Meylikhov. Moscow : Energoatomizdat, 1991.
25. Midea T., Shah J. V. Mold Material Thermophysical Data. AFS Transactions. 2002. Vol. 110. pp. 121–136.
26. Yu K.-O. Modeling for casting and solidification processing. New York : CRC Press, 2001.

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