A model of the interfacial heat-transfer coefficient for the aluminum gravity die-casting process

C. P. Hallam*, W. D. Griffiths

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)

Abstract

Interfacial heat-transfer coefficients were measured during the solidification of Al-Si alloys against coated die steel chills with varying chill temperature, coating thickness and coating type. Two principal resistances to heat transfer across the casting-chill interface were identified, namely, (1) the resistance to heat transfer of the coating itself and (2) the resistance to heat transfer of a layer of gas, (assumed to be air), trapped between the coating and casting surfaces by virtue of their roughness. These thermal resistances were evaluated by measurement of the coating thermal conductivity and determination of the thickness of the applied coatings and the thickness of the layer of air between the coating and casting surfaces. This produced a simple equation to predict the interfacial heat-transfer coefficient during the solidification of Al alloy die castings, which produced values that were found to agree well with the experimentally determined results. This equation was used to interpret the experimentally measured heat-transfer coefficients and to explain their variation with the different experimental conditions employed. A simple modification of the equation can also take into account the formation of an air gap, where the casting locally retreats away from the die surface, leading to a local reduction in the heat-transfer coefficient.

Original languageEnglish
Pages (from-to)721-733
Number of pages13
JournalMetallurgical and Materials Transactions B
Volume35
Issue number4
Publication statusPublished - Aug 2004

ASJC Scopus subject areas

  • General Materials Science
  • Metals and Alloys

Fingerprint

Dive into the research topics of 'A model of the interfacial heat-transfer coefficient for the aluminum gravity die-casting process'. Together they form a unique fingerprint.

Cite this