METHOD OF PRODUCING HIGH QUALITY CASTINGS FROM GREY CAST IRON Russian patent published in 2021 - IPC B22D27/04 

FIELD: foundry engineering.

SUBSTANCE: cast iron is poured into the mold made out of wet sand-clay, the mold is blown through with compressed air and the casting is shaken out. The blowing is done with compressed air with atmospheric oxygen consumption rate between 0.03 and 0.07 nm³/m² on the surface of the casting simultaneously with pouring of the iron, continuously until the casting is solid. A mold is used containing between 0.5 and 3.0 weight parts of exothermic carbonaceous additions. Supply of compressed air simultaneously with pouring in the cast iron leads to increased speed of melt cooling in the interval of dendrite crystallization of primary austenite which raises the dispersity of the dendrite frame of cast iron structure. Meanwhile, the heat emitted by the molding evaporates the moisture of the mold and saturates it with hot atmospheric oxygen which initiates combustion of the exothermic carbonaceous additions of the mold. Thermal energy discharge slows down the cooling of the casting in an interval of eutectic transformation which increases graphitization of the iron and results in graphitic eutectic.

EFFECT: simplification of a method of production of high-quality castings from grey cast iron is achieved.

1 cl, 1 tbl, 1 ex