Accurate Simulation of Complex Temperature Field in Counter-Pressure Casting Process Using A356 Aluminum Alloy

Abstract

Automobile steering knuckle is an important part of the steering system, which is subjected to significant impacts and loads during its operation. Generally, cast aluminum steering knuckles are usually produced using some type of enhanced low-pressure casting process, like counter-pressure casting. Compared with aluminum forging and sand cast ductile iron, it can improve the production speed and achieve the adequate casting quality. In this study, various methodologies such as dynamic thermomechanical analysis, differential scanning calorimetry, and the laser flash method were employed to study the thermophysical properties of AlSi7Mg0.3. Further, the physical model of a counter-pressure casting system with an aluminum interior was established based on the combination of the tested and the theoretical properties of aluminum; this was achieved with the consideration of the presence of other factors including rapid solidification. The temperature field of the system was computed and verified by thermocouples at six different points during the tooling and the shrinkage simulation. It was observed that the plot shape of the computed temperatures and that of the simulated ones correlated; further, the difference between the peaks and the valleys was controlled to be 3% on an average, with the maximum variation of 7% at only one point. Moreover, all the predicted shrinkages were verified by the casting. This study provides a solid foundation for facilitating the simulation of the morphologies of the microstructure.