Patent ID: 7017646

Claim:
A method of casting a directionally solidified (DS) or single crystal (SX) article with a casting furnace having a heating chamber with at least one heating element, a cooling chamber, and a separating baffle between the heating and the cooling chamber, the method comprising: feeding the shell mould within the heating chamber with liquid metal through a filling device; withdrawing the shell mould from the heating chamber through the baffle to the cooling chamber and thereby directionally solidifying the liquid metal forming the cast article; after withdrawing an initial 5–50 mm of the shell mould into the cooling chamber, impinging an inert gas from nozzles arranged below the baffle on the shell mould and thereby forming an impingement area; at least reducing, in steep increase in outer surface area or a protruding geometrical feature of the shell mould, the flow of the inert gas; and when the steep increase or protruding geometrical feature has passed the impingement area of the gas jets, restoring the gas flow to a value adjusted to the geometry of the cast part presently passing the impingement area.