Modeling of Transport Phenomena in Low-Head Direct-Chill Caster for AA7050 Alloy

Abstract

As an extension of earlier work, a three-dimensional numerical model has been developed for an industrial-scale low-head direct-chill slab casting process for the long freezing range aluminum alloy AA7050. The model has taken into account the coupled nature of the turbulent melt flow and the solidification heat transfer aspect of the direct-chill casting process. Computer simulations were performed to predict the velocity and temperature fields, the sump profile, the mushy thickness, and the shell thickness at the exit of the mold. Specifically, the aforementioned results were obtained for four casting speeds, varying from 60 to , for three metal–mold effective heat transfer boundary conditions, varying from 1.0 to , and for three pouring temperatures of inlet melt, namely, 645, 661, and 693°C. A stepwise change of the cooling water temperature in the mold and impingement and free-streaming regions, were considered to reflect the temperature history of the cooling water conditions in the industry. The importance of the present study lies in the fact that, by rolling the cast slabs from the direct-chill process, the obtained plates, sheets, strips, and foils of the aforementioned alloy are used extensively by the aerospace industry.