ANNULAR TAPER FEEDER HEAD OF CERAMIC MOULDS Russian patent published in 1995 - IPC

FIELD: casting process. SUBSTANCE: the bottom portion of an annular taper feeder head has a necking next to the hot top portion of the casting, the dimensional relationship between the necking and the hot top portion of the casting being B=(0.4 to 0.6)B = (0,4÷ 0,6)δ and h=(1.0 to 1.8)n = (1,0÷ 1,8)δ. When molten metal poured into the feeder head passes the necking, the latter's temperature rises almost to that of the metal. Heat waves emanating from the metal superimpose each other in the necking, bringing about there an accumulation of significant heat under the conditions of low-rate heat transfer from the necking into the feeder head. A hot crust formed in the necking is a factor conducive to reducing the cross section of the feeder to 0.5 0,5δ by adopting the right depth of necking, B, variable between 1.0 B = (0,4÷ 0,6)δ and 1.8 n = (1,0÷ 1,8)δ. This means that the hot top portion of the casting is diminishable in size and drawn inside the crop from the zone below the feeder head. The necking at the lower end of the feeder head reduces the requirements in cutting tools for croppage, cuts the consumption of metal for moulds and minimizes the crop length. EFFECT: elimination of shrinkage porosity from the zone of casting below the feeder head and increase in the amount of sound metal in the casting. 1 cl, 1 dwg, 1 tbl