DRUŠTVO LIVARJEV SLOVENIJESLOVENIAN FOUNDRYMEN SOCIETY
Član The World Foundry OrganizationMember of World Foundry Organization

Abstract

Institute of Joining and Welding, Braunschweig University of Technology, Braunschweig, Germany

High-pressure die-casting dies are subjected to high cyclic temperatures and mechanical loads. Heating and cooling cycles cause thermal expansion and contraction of the material, generating strain fields which lead to a significant plastic deformation. An accumulation of plastic deformations often leads to unexpected failures at the surface of the die-casting die. The selection, quality and the pro-cessing (e. g. heat treatment) of hot work tool steels are parameters that are often discussed in scien-tific literature. However, the temperature control of the die-casting die is another important parameter for the achievement of reasonable lifetimes. The article illustrates, how characteristic properties of conventional internal cooling systems (e. g. the wall heat transfer coefficient and the pressure drop) can be calculated by CFD simulation (ANSYS CFX) and verified by experimental investigations. The calculated specific values for the pressure drop and the wall heat transfer coefficient were processed and transformed into engineering specifications. Using this knowledge, the design process of the cool-ing system is more accurate than an estimated guess based on gained practical experience. However, due to restrictions in the performance of conventional cooling systems, an alternative method to estab-lish conformal cooling channels is discussed: the segmentation of the die-casting tool. In order to demonstrate the potential, advantages and restrictions of this method, an existing die-casting tool insert is used. The article finishes with a brief summary and an outlook on further improvements to the approaches.

Keywords: die-casting, design process, temperature control, CFD analysis, conformal cooling channels