Prediction of Laminations in Zinc Alloy Die–Casting by Gas–Liquid Two–Phase Flow Simulation

In the manufacturing process of zinc alloy die–casting, laminations are a serious problem because they cause blister defects and the deposition of zinc on the mold surface. Thus, it is very important to analytically predict the risk of lamination formation before determining the mold design. In this study, we proposed a criterion for predicting the locations of laminations. The criterion value is estimated from the result of a molten metal flow simulation and can indirectly predict the locations of laminations. As the analytic method in the mold–filling simulation, we adopted a gas–liquid two–phase flow model with a finite element method, and the Cahn–Hilliard equation was adopted to determine the interface between the gas and the liquid. We predicted the locations of laminations for two different types of gating system using the mold–filling simulation. The validity of the proposed criterion for laminations was confirmed by comparison of the results of the simulation and the observation of laminations after practical die–casting. © 2021 The Japan Institute of Metals and Materials