Effect of cooling water quality on dendrite arm spacing of DC cast billets

Abstract

For a given alloy chemistry & casting technology, the quality of a billet produced through DC (Direct Chill) casting route is largely defined by the DAS (Dendrite arm spacing). DAS in turn, is determined by the cooling rate and local solidification time. The cooling rate is influenced by the quality & quantity of water besides casting speed and melt temperature. This paper focuses on the relationship between the quality of cooling water & the resultant DAS during production of DC cast billets. An empirical relation is derived to indicate the influence of cooling water characteristics on the DAS, based on a mathematical model supplemented by experimental investigations. The model has been validated in plant scale trials.