Considerable progress has been made in recent years with theoptimisation of grain refinement practice. In the past this couldonly be done by trial and error which is time consuming and farfrom ideal. More recently it has been possible to study andquantify the various factors affecting grain refinement includingmelt nucleation level, growth restriction, grain refiner recovery, inline treatments and potency and variation in grain refiners with thehelp of the Opticast technology which allows data to be generatedfrom sampling the melt in real time. It has been found that whilstit is useful and necessary to quantify the foregoing furnace factorsit is equally necessary to control grain refiner variation in order toachieve a fully optimsed result and to support this, a new grainrefiner, Optifine, has been developed and introduced in a numbercasthouses. The results from two casthouses where thesetechniques have been applied are reviewed.
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