More investment casting defects pdf operation for the personnel. Graphite molds are commonly used in the horizontal continuous casting methods.
Withdrawal the casting at a rate providing required production capacity. Effective heat extraction by the cooling system allows to cast at high speed. Providing stable and steady casting process. Formation of fine and homogeneous Grain structure. Diminishing the thickness of the defective surface layer. This layer is commonly machined prior to metal forming processing. Preventing formation of transverse and longitudinal cracks.
Primary cooling – extraction of the solidifying metal heat through the mold walls. Secondary cooling is not always necessary. Thin strips and alloys susceptible to thermal stresses are cast without secondary cooling. In this mold its surface is sprinkled by water stream. This type of cooling is very effective due to elimination of air gap between the graphite mold surface and the coolers. High cooling rates achieved in the directly water-cooled mold allow to use short molds and reach relatively high withdrawal speeds. Graphite mold cooled by water-cooled copper blocks.
Cooling rate in this method is relatively low due to the air gap between the graphite mold surface and the surfaces of the copper coolers. Molds of this type are longer than directly water-cooled graphite molds. The break ring should conform the mold cross-section. The enter tip of the graphite mold is prominent into the holding vessel space and submerged into the melt.