METHOD OF HIGH-STRENGTH CAST IRON PRODUCTION Russian patent published in 2002 - IPC

FIELD: metallurgy, foundry, particularly, methods of production of high-strength cast iron from initial pig iron. SUBSTANCE: method includes smelting of charge in smelting unit, bringing temperature of smelt up to 1420-1480 C, initial inoculation up to appearance of effect of overinoculation of cast iron. Inoculation is carried out with use of alloying composition containing, %: rare-earth metals, 8-40; silicon, 20-60; aluminum, 0.1-15; calcium, 0.5-6; magnesium, 0.1-3; copper, 0.1-2.5. Secondary inoculation is effected with use of alloying composition containing rare-earth metals, magnesium and silicon in amount of 0.1-1.2% of melt weight at temperature of 1300-1400 C. Said method is used in mass production of castings from high-strength cast iron with spherulitic and verticular graphite. EFFECT: higher process stability, reduced of cost of production due to use of low-cost alloying compositions, reduced rejects of nonstandard cast-iron grade. 9 cl, 2 tbl