Veining or finning constitutes a very frequent type of defect that occurs particularly in association with cold box chemically bonded sand systems. Veining arises as a result of penetration of the molten metal into cracks on the mold or core surface.
Crack formation is due to the thermal stressing of the molding material arising from progressive quartz sand expansion at elevated temperatures and the subsequent cooling and contraction associated with the casting and solidification processes. Imerys additives for cold box binder systems prevent the formation of these cracks ensuring the attainment of smooth and defect-free cored surfaces in the as-cast condition reducing the necessity for further processing.
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