PROCEDURE FOR CRUMBLING GRAPHITE INCLUSIONS IN HIGH STRENGTH IRON Russian patent published in 2010 - IPC C21C1/00 

FIELD: metallurgy.

SUBSTANCE: procedure consists in melting iron in induction electric furnace and in primary and secondary inoculation. Primary inoculation is performed with fine fraction ferrosilicon FS75 at amount of 0.15-0.20% of melt weight, while secondary inoculation is performed with complex alloy consisting of 70% of FSMg-7 and 30% of SIBAR22 at amount of 2.0-2.5% of melt weight. Alloying, conditioning and inoculation of melt are carried out till iron reaches eutectic composition in wt %: carbon - 3.10…3.25; silicon - 3.70…4.00; manganese - 0.20…0.25; copper - 1.00…1.50; phosphorus - 0.02…0.03; sulphur - 0.01…0.012; magnesium - 0.04…0.07; iron - the rest. Primary inoculation is executed on spout at melt tapping into a ladle or in a casting ladle proper. In this case secondary inoculation is performed in a mould, while amount of complex inoculants is decreased to 1.0-1.5% of melt weight. Primary inoculation can be performed in an induction mixer. Conditioning time between primary and secondary inoculation should not exceed 3 minutes.

EFFECT: upgraded mechanical and operational properties of iron.

6 cl, 2 ex, 2 tbl