METHOD FOR PREVENTING COARSE ALUMINA IN HIGH CARBON CHROME BALL BEARING STEEL FROM BEING FORMED

摘要

PURPOSE:To manufacture high carbon chrome bearing steel being excellent in a fatigue characteristic by preventing coarse alumina in the high carbon chrome ball bearing from being formed. CONSTITUTION:At the time of manufacturing an ingot by a continuous casting method from molten steel of a composition corresponding to high carbon chrome ball bearing steel (JIS standard SUJ), a relation of a degree of oxidation of slag R(=FeO+Fe2O3+MnOweight%) existing in a tundish for continuous casting and the sol. Al contact (sol. Alweight%) in the molten steel is controlled in accordance with R=-100 (sol. Al%). In such a way, it is prevented that alumina in the high carbon chrome bearing steel becomes bulky due to clustering, and by following it, size becomes minute. As a result, high carbon chrome ball bearing steel being excellent in a rolling fatifue service life is obtained.