A Control System Analysis of a Direct-Chill Cast Process of Aluminum Ingots by an Inverse Measured Method

A direct-chill (DC) cast process of an aluminum ingot of size 3200×1292×320 mm3 is analyzed numerically by the analysis of a fixed controlled system. The study investigates the DC processes in which liquid aluminum is cooling continuously in mold and then with water spray at the exit of mold. An inverse method is applied to measure heat transfer coefficient on water cooling surface experimentally. A correlation of heat transfer coefficient with surface temperature is used in numerical simulation. It has been approved that the defected curl and tears are caused by the higher rates of initial cooling and solidifying in mold and the sweat and liquation are caused by the isolation of heat transfer by air gap formed between cast solid surface and the mold wall by volume shrinkage with solidification. The present research analyzes the variations of temperature profiles in the cast ingot by the changes of cast speed and cast temperature and assesses the improvements of mold and cast process for the better cast quality.