Metal casting

摘要

A method of growing a single crystal seed bar (10) in which a mould provided with a grain selector filter (16) above a starter chamber is filled with molten metal, whereupon the metal is allowed to solidify slowly upwardly from the starter chamber. The filter (16) is provided with a pattern of openings, with the diameter of the openings being at least as large as the primary dendrite tip radius of the metal, but smaller than half the primary dendrite arm spacing.