Bearing steel and ingot material for bearing having excellent rolling contact fatigue life characteristics and method for manufacturing the same

Abstract

The present invention has a component composition which comprises 0.56 to 0.70 mass% of C, 0.15 mass% or more but less than 0.50 mass% of Si, 0.60 to 1.50 mass% of Mn, 0.50 to 1.10 mass% of Cr, 0.05 to 0.5 mass% of Mo, 0.025 mass% or less of P, 0.025 mass% or less of S, 0.005 to 0.500 mass% of Al, 0.0015 mass% or less of O, 0.0030 to 0.015 mass% of N, and residual Fe and inevitable impurities as the balance, and which has an eutectic carbide generation index (Ec) that is 0<Ec=0.25 and an Mo segregation degree that is 2.8 or less.

Description

technical field [0001] The present invention relates to a material having excellent rolling contact fatigue life characteristics suitable as a material for bearings used in automobiles, wind power, conveying machinery, electrical machinery, precision machinery, and other general industrial machinery, etc. Bearing steel and its manufacturing method. Background technique [0002] As such a bearing steel, high carbon chromium steel (high carbon chromium steel: JIS G4805 standard SUJ2) is often used. In general, for bearing steels, excellent rolling contact fatigue life characteristics are one of the important properties, and the rolling contact fatigue life is reduced by non-metallic inclusions or eutectic carbides in the steel. [0003] In recent studies, it is believed that non-metallic inclusions in steel most affect the reduction of rolling contact fatigue life, and have been taking measures to control the amount and size of non-metallic inclusions by reducing the oxygen c...

AI Technical Summary

Problems solved by technology

[0014] However, there is a problem that although the rolling contact fatigue life characteristics can be improved by performing the above-mentioned carburizing or carbonitriding, it causes an increase in manufacturing cost, or a decrease in yield due to large deformation and dimensional changes, resulting in rising product costs

[0015] In addition, there is also a problem that, depending on the application of the bearing steel, a larger section is required, so that a large-scale modification of the equipment for carburizing or carbonitriding is required, and the economic burden is heavy.

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