METHOD OF MANUFACTURING BEARING STEEL INGOTS Russian patent published in 1999 - IPC

FIELD: steelmaking. SUBSTANCE: method consists in smelting steel and casting it through bottom gate into molds into which, preliminarily, slag-like mixture in amount 1.3-2.5 kg per 1 t steel has been added. This mixture contains 30-50% of gas-treatment dust from ferrosilicon production, 17-37% of gas-treatment dust from aluminum production, 20-35% of lime dust, and up to 3% of graphite. Resultant slag with ratio CaO/SiO₂ =0.7-1.0 is composed of, wt %: CaO 33.0-32.0, SiO₂ 26.0-38.0, Al₂O₃ 6.0-22.0, CaF₂ 4.0-10.0, K₂O 0.5-5.0, Na₂O 0.5-5.0, MgO less than 2.0, FrO less than 1.0, MnO less than 1.0. After casting, molds are mechanically cleaned to remove wall accretion. EFFECT: increased yield of valid product due to reduced surface defects. 1 tbl