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<p>Using a reliable value for the heat transfer coefficient (HTC) at the mold–metal interface for the purpose of modeling the filling and solidification inside a mold is a recurrent issue. Numerous measurements have been taken for simple geometries showing that HTC varies during the course of solidification, dropping sharply when an air gap forms at the interface. Also, HTC at the bottom of a horizontal plate casting is often higher than at the top surface. Whether dealing with green sand or “no-bake” sand, particularly in the early phase of the filling and solidification processes, water evaporation or resin melting and cracking of the polymer molecules absorb an amount of heat which results in a considerable increase in the apparent heat capacity of the sand. Since these phenomena cannot be modeled, an “effective” value of the HTC is usually defined which depends on the casting size, the nature of the sand and of the binder. For this reason, these “effective values” should be determined in-house on a variety of conditions; this implies that the empirical determination of HTC should be simple. In this paper, a method is proposed where recording the response of two thermocouples is sufficient to determine the interfacial HTC during the filling and solidification phases of the casting process. This will be demonstrated on a magnesium ZE41A casting with 20kg (44lb) of poured metal resulting in an 8kg (18lb) trimmed casting.</p>

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Measuring the Effective Heat Transfer Coefficients at the Mold–Metal interface in a Sand Casting for the Purpose of Solidification Modeling

  • 期刊论文

  • 发表日期：

    2026年3月16日

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  • Franco Chiesa,
  • Jimmy Simard,
  • David Levasseur,
  • Gheorghe Marin

摘要

Using a reliable value for the heat transfer coefficient (HTC) at the mold–metal interface for the purpose of modeling the filling and solidification inside a mold is a recurrent issue. Numerous measurements have been taken for simple geometries showing that HTC varies during the course of solidification, dropping sharply when an air gap forms at the interface. Also, HTC at the bottom of a horizontal plate casting is often higher than at the top surface. Whether dealing with green sand or “no-bake” sand, particularly in the early phase of the filling and solidification processes, water evaporation or resin melting and cracking of the polymer molecules absorb an amount of heat which results in a considerable increase in the apparent heat capacity of the sand. Since these phenomena cannot be modeled, an “effective” value of the HTC is usually defined which depends on the casting size, the nature of the sand and of the binder. For this reason, these “effective values” should be determined in-house on a variety of conditions; this implies that the empirical determination of HTC should be simple. In this paper, a method is proposed where recording the response of two thermocouples is sufficient to determine the interfacial HTC during the filling and solidification phases of the casting process. This will be demonstrated on a magnesium ZE41A casting with 20kg (44lb) of poured metal resulting in an 8kg (18lb) trimmed casting.