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Determination of heat transfer coefficients by extrapolation and numerical inverse methods in squeeze casting of magnesium alloy AM60

Authors :
Sun, Zhizhong
Hu, Henry
Niu, Xiaoping
Source :
Journal of Materials Processing Technology. Aug2011, Vol. 211 Issue 8, p1432-1440. 9p.
Publication Year :
2011

Abstract

Abstract: In this work, a different wall-thickness 5-step (with thicknesses as 3, 5, 8, 12, 20mm) casting mold was designed, and squeeze casting of magnesium alloy AM60 was performed under an applied pressure 30, 60 and 90MPa in a hydraulic press. The casting–die interfacial heat transfer coefficients (IHTC) in the 5-step casting were determined based on thermal histories throughout the die and inside the casting which were recorded by fine type-K thermocouples. With measured temperatures, heat flux and IHTCs were evaluated using the polynomial curve fitting method and numerical inverse method. For numerical inverse method, a solution algorithm was developed based on the function specification method to solve the inverse heat conduction equations. The IHTCs curves for five steps versus time were displayed. As the applied pressures increased, the IHTC peak value of each step was increased accordingly. It can be observed that the peak IHTC value decreased as the step became thinner. Furthermore, the accuracy of these curves was analyzed by the direct modeling calculation. The results indicated that heat flux and IHTCs determined by the inverse method were more accurately than those from the extrapolated fitting method. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
09240136
Volume :
211
Issue :
8
Database :
Academic Search Index
Journal :
Journal of Materials Processing Technology
Publication Type :
Academic Journal
Accession number :
60158570
Full Text :
https://doi.org/10.1016/j.jmatprotec.2011.03.014