Method for casting a directionally solidified article

摘要

A method of casting a directionally solidified (DS) or single crystal (SX) article with a casting furnace having a heating chamber ( 4 ), a cooling chamber ( 5 ), a separating baffle ( 3 ) between the both chambers includes a first step in which the shell mould ( 12 ) is filled with liquid metal ( 15 ), and the liquid metal ( 15 ) is directionally solidified by withdrawing the shell mould ( 12 ) from the heating to the cooling chamber ( 4, 5 ). An inert gas impinges from nozzles ( 8 ) arranged below the baffle ( 3 ) on the shell mould ( 12 ) and in steep transitions in outer surface area of the shell mould ( 12 ) the flow of the inert gas ( 9 ) is reduced or even stopped and when a protruding geometrical feature has passed the impingement area of the gas jets, the gas flow ( 9 ) is restored to a value adjusted to the geometry of the cast part presently passing the impingement area.