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Publication of GB993097ApublicationCriticalpatent/GB993097A/en
993,097. Mould and core materials. SCHWERMASCHINENBAU ERNST THALMANN VEB. Oct. 23, 1963, No. 41845/63. Heading B3F. The inner surface of a foundry mould is lined with two layers of material comprising a thin inner layer with which the molten metal comes in contact and an outer layer of greater thickness then the inner layer. The inner layer is formed from a highly refractive insulating material and the outer layer contains a filler and a reducing agent. The reducing agent is preferably a hydrocarbon or carbon material which when the mould is in use prevents oxygen from the surrounding atmosphere permeating into the mould. The reducing agent may be in the form of anthracite, briquette tailings, coke or brown coal coke. A particularly suitable composition is 60% fine quartz sand, 10% quartz powder, 10% fireclay powder, and 20% clay.