A Statistical Evaluation of the Influence of Different Material and Process Parameters on the Heat Transfer Coefficient in Gravity Die Casting

Abstract

Local heat transfer in gravity die casting is of great importance for precision in terms of distortion, mechanical properties, and the quality of the castings due to its effect on solidification. Depending on contact conditions such as liquid melt to solid mold, a gap between mold and component, or contact pressure between casting and mold as a result of shrinkage, there are very large differences in heat transfer. The influences of mold material, mold coating and its influence of aging, mold temperature control, and layout on the heat transfer coefficient (HTC) were investigated experimentally for different contact cases. The experiments were carried out on a rotationally symmetrical experimental setup with modular exchangeable die inserts and cores using an AlSi7Mg0.3 alloy. From the results of the individual test series, the quantitative shares of the above-mentioned influencing variables in the respective effective heat transfer coefficients were determined by means of analysis of variance. From this, the parameters having the most significant influence on the local heat balance were derived.

Development of an Experimental Setup to Investigate Influences on Component Distortion in Gravity Die Casting and a First Variation of Temperature Control Strategy

“…The use of two oil temperature control units (type 1502/12 by Thermobiel Apparatebau GmbH, Gladbeck, Germany) with a total of four circuits, that can be set up independently from ambient up to 350 • C medium temperature and with a flow rate of 16 l/min each, enables full thermal control. The die coating was selected to be KS-81 (by Hüttenes-Albertus, Düsseldorf, Germany) from the previous works [1][2][3]. The measuring devices to measure the relative movement of the part and the contact pressure were also adopted from these previous test setups, with which the gap and contact pressure dependent heat transfer coefficients were determined.…”

“…The long-term goal of this sub-project, on which the work presented here is based on, is to improve component precision in permanent mold casting by creating a knowledge base in the areas of distortion and hot cracking, and furthermore, the development of corresponding concepts for their prediction, influencing, and minimization. The heat transfer coefficient (HTC) between mold and component, which has already been considered as a possible major influencing factor, was analyzed in this project in several separate studies [1][2][3]. In addition to these primarily experimental studies, in closely related subprojects, the working group is developing numerical methods to advance the coupled thermomechanical simulation on both the macroscale and the microscale [4,5].…”

Numerical Simulation and Experimental Study on Compound Casting of Layered Aluminum Matrix Composite Brake Drum

“…Some studies have shown that the applied pressure will affect the interface heat transfer coefficient between the metal melt and the metal die [ 47 , 48 , 49 , 50 , 51 ]. It is generally believed that the liquid contacts the metal surface more closely after the melt is pressurized.…”

Advances in Metal Casting Technology: A Review of State of the Art, Challenges and Trends—Part II: Technologies New and Revived

“…Here, the correct representation of heat transfer coefficients over time, including effects like the formation of gaps between the casting and the die, remains an area of research [281]. This is illustrated by the fact that two contributions to the present Special Issue are related to the topic [282,283].…”

“…The studies by Wolff et al [283] and Kouki et al [282] are linked to virtual casting and simulation approaches, as they both consider the heat transfer coefficient (HTC), a crucial though difficult to determine parameter in casting. Kouki et al propose and evaluate a tool for measuring time-dependent HTCs in permanent mold casting.…”