METHOD OF STEEL MAKING Russian patent published in 2003 - IPC

FIELD: non-ferrous metallurgy; making high-quality steels. SUBSTANCE: proposed method includes deoxidation of metal by aluminum in two portions. First portion is introduced in the course of heat tapping in the amount determined by the following expression M+A/(1+15xC), where M is mass of aluminum, kg/t; C is content of carbon before tapping, mass-%; A is coefficient equal to 2.2-2.5 kg/t. Second portion of aluminum is introduced after heat tapping at simultaneous mixing with argon at flow rate of 0.1-0.2 cu m/t.h continued till oxygen activity in metal has reached 5-10 ppm. Then metal is alloyed with silicon-containing ferroalloys. Flow rate of argon is increased by 0.005-0.015 cu m/t.h per kg/t of added ferroalloys. EFFECT: reduced level of fouling metal with non-metallic inclusions due to optimization of deoxidation and alloying processes. 1 tbl