In this paper, the development of an experimental die casting setup to perform simultaneous in-situ measurements of temperatures, air-gap formation and contact pressures is presented. The derivation of the resulting heat transfer coefficients between mold and melt is also included. To take the influence of different cooling rates into account, an active die tempering is applied. For the implementation of this experimental setup, a special mold for a rotationally symmetrical test specimen is developed which incorporates the necessary measuring technique and can be adapted to different cooling conditions by means of exchangeable die inserts. Concluding, first results and the corresponding heat transfer coefficients are presented.Keywords: Heat transfer coefficient / air-gap formation / contact pressure / mold tempering / permanent mold casting Es wird die Entwicklung eines Kokillenguss-Versuchssaufbaus vorgestellt, um gleichzeitige in-situ Messungen von Temperaturen, Spaltbildung und Kontaktdrücken zu ermö glichen, genauso wie die Ermittlung der sich daraus ableitenden Wä rmeü bergangskoeffizienten zwischen Form und Gussteil. Dabei wird der Einfluss von verschiedenen Abkü hlraten durch aktive Formtemperierung berü cksichtigt. Hierfü r wird eine spezielle Form fü r ein rotationssymmetrisches Gussteil entwickelt, die die nö tige Messtechnik aufnehmen sowie durch wechselbare Formeinsä tze an verschiedene Abkü hlbedingungen angepasst werden kann. Es werden erste Ergebnisse inklusive der zugehö rigen Wä rmeü bergangskoeffizienten vorgestellt.Schlü sselwö rter: Wä rmeü bergangskoeffizient / Spaltbildung / Kontaktdruck / Formtemperierung / Dauerformguss Figure 6. Values of the air-gap related heat transfer coefficient for different die temperatures versus the corresponding cast interface temperature. On the right side for the complete solidification process and on the left side a cut out with a smaller temperature range. N. Wolff et al.

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Anticipating the processes and parameters involved for accomplishing a sound metal casting requires an in-depth understanding of the underlying behaviors characterizing a liquid melt solidifying inside its mold. Heat balance represents a major factor in describing the thermal conditions in a casting process and one of its main influences is the heat transfer between the casting and its surroundings. Local heat transfer coefficients describe how well heat can be transferred from one body or material to another. This paper will discuss the estimation of these coefficients in a gravity die casting process with local air gap formation and heat shrinkage induced contact pressure. Both an experimental evaluation and a numerical modeling for a solidification simulation will be performed as two means of investigating the local heat transfer coefficients and their local differences for regions with air gap formation or contact pressure when casting A356 (AlSi7Mg0.3).