METHOD OF CASTING UNDER LOW PRESSURE INTO METAL MOULD Russian patent published in 2024 - IPC B22D18/04 B22D27/09 

FIELD: foundry.

SUBSTANCE: method of low-pressure casting into a metal mould involves filling the metal mould with a melt under the action of excess gas pressure in a furnace, which is varied at preset casting stages. At 1st stage, in range from 0 to 15 s, the excess gas pressure in the furnace is increased from 0 to 17,500 Pa. At 2nd stage, with duration of 12-50 s, the mould is filled with increase of the specified pressure along an exponential curve with a damping rate to the end of the mould filling with achievement of the specified pressure of 15,000-50,000 Pa. At 3rd stage, 40-65 s from the moment of filling the mould, it is held for 15-20 s at constant level of the specified pressure. At 4th stage, in range of 55-85 s, the specified pressure is increased from 45,000 to 65,000 Pa. At 5th stage, in range of 70-650 s, pressure is maintained at the same level until complete crystallisation of the casting. At 6th stage, in range of 600-800 s after complete crystallisation of the casting, the specified pressure is gradually reduced to 0 Pa.

EFFECT: reduced number of rejects in the production of castings.

7 cl, 1 dwg, 1 ex