FIELD: ferrous metallurgy. SUBSTANCE: method includes preparing basic smelt using modifying substance, controlling and adjusting composition of smelt by sampling with sampling device, one of its heat sensor being disposed in the center of device and the other near its wall. To the sample in sampling device, necessary amount of oxides, sulfides, and oxido- sulfides is added to oxidize modifying substance contained in sample and provide decay of these reactions during entire casting operation. In the course of hardening of smelt in sampling device, temperature is recorded at different time intervals and degree of sphericity of separating graphite inclusion bodies is evaluated. If degree of sphericity of these bodies is to be increased, additional amount of modifier is added. EFFECT: reduced consumption of modifying substance at no risk of incomplete formation of graphite grains. 6 cl, 2 dwg, 2 ex
