ABSTRACT
The direct-chill (DC) casting process is an important method for the production of a number of nonferrous metal products. Among these are the aluminium extrusion ingots and rolling sheet ingots. A schematic drawing of the DC casting process for sheet ingots is depicted in Fig. l. A starting block is initially positioned inside a bottomless, water-cooled mold. During casting superheated liquid metal is fed into the mold through a nozzle or launder. When the metal starts to solidify, the starting block, placed on top of a casting table, is lowered. From holes or slits in the lower part of the mold, a water jet impinges on the ingot surface as this is lowered from the mold. Heat transfer from the cast metal to the mold is called primary cooling, whereas the heat transfer to the direct water cooling is called secondary cooling.
