Three-Dimensional CFD Simulation Coupled with Thermal Contraction in Direct-Chill Casting of A390 Aluminum Alloy Hollow Billet

A three-dimensional CFD model coupled with melt flow, heat transfer, and thermal contraction was developed to simulate the direct-chill (DC) casting process of A390 alloy hollow billet with a cross-section size of Φ164 mm/Φ60 mm. This study considered the effects of contact height and air gap width between the core and the hollow billet, which dominated the heat transfer at the inner wall of the hollow billet. The effects of core taper angle, relative vertical position of core in the mold, and casting speed on the steady-state temperature distribution and formability of hollow billet were investigated. According to the criterion used in this study, the optimal core taper angle is 3 deg for DC casting of A390 alloy hollow billet. With the optimal core taper angle, the A390 alloy hollow billet can be cast successfully regardless of the variation of the relative vertical position of core in the mold and casting speed. The coupled model developed in this study can be applied to optimize the core taper angle and study the effects of casting parameters in various dimensions of hollow billet.