Numerická štúdia vplyvu teploty jadra na tepelné zaťaženie vysokotlakovej formy pri výrobe odliatkov pre EC motory

Abstract

Thermal loading of the die in high-pressure die casting is a complex phenomenon driven by the interaction of the molten metal with the die surface. This interaction leads to cyclic temperature changes, steep thermal gradients, and thermal shock, all of which significantly impact the integrity of the die. During each injection cycle, dramatic temperature changes occur on the die surface. Molten aluminum comes into contact with the die surface, which can reach peak temperatures exceeding 450°C, causing high temperature fluctuations. The aim of the experiment was to investigate the influence of two different thermoregulation media - water and ITERM 6MB heat transfer oil - on the thermal behavior of the die cores for EC 75 and EC 55 castings. Experimental results showed that water cooling leads to more efficient heat dissipation and lower temperatures in the core, while oil tempering ensures higher and more stable temperatures. Analysis of the temperature distribution in the die closing and opening phases confirmed that while water cooling leads to more intensive cooling, oil tempering contributes to a more uniform thermal regime and a potential reduction in thermal shock, which is crucial for die life and casting quality. Significant differences were observed in the cores' thermal behavior for EC 75 and EC 55 castings, despite their differing tubular section heights.