Reducing the grain size of cast aluminium alloys - by retarding grain-refinement in blocks for remelting

摘要

In the mfr. of Al or Al alloy blocks intended for remelting, e.g. in foundries, B, Ti or a similar material in the form of a pre-alloy or salt is added to the initial melt. The novelty is that the grain-refining agent is added immediately prior to, or during the casting of the blocks so solidification occurs before expiry of the incubation time needed for max. grain-reinfinement, i.e. before 30 mins. and pref. before 20 mins. Better grain-refining when remelting blocks and slower grain growth during holding times. are obtd.