METHOD FOR MAKING CAST IRON WITH DIFFERENT TYPE OF GRAPHITE Russian patent published in 2002 - IPC

FIELD: metallurgy, namely foundry, particularly production of cast irons with different form of graphite. SUBSTANCE: method comprises steps of loading charge into furnace; melting it under main slag-forming material until providing predetermined total content of carbon and silicium in melt; overheating melt until predetermined temperature; introducing aluminum and then soaking for time period no more than 30 min; draining slag and modifying melt in ladle with calcium-silicon in quantity (1.0-1.5)% of mass of melt metal in ladle; using flux in quantity consisting (0.3-1.5)% of mass of melt metal as main slag-forming material; after achieving predetermined temperature, soaking melt for 1-7 minutes; draining slag; adding aluminum onto metal heel in quantity consisting (1.2-3.5)% of mass of melt metal; then creating new covering layer of flux. Such method allows to eliminate whitening at centrifugal and continuous casting, to increase range of cutting capability and rigidity up to HB 190-400; to receive structure with pearlite content 96% and to provide uniform rigidity and structure of superthin castings. EFFECT: enlarged range of casting without whitening, enhanced quality of cast iron. 1 tbl, 1 ex