Casting of metal objects

摘要

A mould assembly comprising mould segments of generally non-thermally conductive material which define a mould cavity is upwardly filled with liquid metal through at least one in-gate. A thermal extraction member of a high thermally conductive material contacts a portion of the mould cavity through which heat is extracted rapidly to establish positive thermal gradients in the casting and thereby promote directional solidification. The mould assembly is also provided with a seal to selectively isolate the mould assembly from the liquid metal source to allow the mould assembly to be removed from the casting station and transferred to the cooling station, providing a more efficient use of the casting station. In addition, once a shell has solidified then the mould segments and metal contained therein can be transferred to the cooling station.