In centrifugal casting, the molten metal is poured into a steel mould, which rotates around its axis either horizontally (shown in the picture) or vertically. The exterior of the mould is cooled with water to ensure directional solidification. The method produces dense castings of consistent quality. During the casting process, any porosity present in the molten metal becomes localised to the inner layer, which is removed by machining.
In the continuous casting technique, the molten metal is poured from a furnace to a graphite die, via a crucible. The die is cooled with the aid of a water-cooling jacket, to guarantee directional solidification. In the casting of hollow billets, a mould is placed inside the die to produce the interior shape for the billet. This method allows the production of precisely dimensioned billets for further machining. Billets intended for automatic machining must be straightened before delivery.