To provide a novel four-row tapered roller bearing capable of maintaining its function over a long period even under bad and severe environment such as a rolling process of a steel industrial machine.
The four-row tapered roller bearing comprises four rows of rollers provided between an inner ring and an outer ring along the peripheral direction. At least the outer ring and each tapered roller are formed of steel materials consisting of 0.1-1.2 mass% C, 0.1-1.0 mass% Si, 0.4-1.4 mass% Mn, 0.5-2.0 mass% Cr, 0.5-2.0 mass% Mo, and residual Fe and inevitable impurities. After they are subjected to carburizing or carbonitriding treatment, their surface layer portions contain 0.8-1.2 mass% C and 0.01-1.00 mass% N. Thus, the bearing has improved wear resistance and seizure resistance, and so maintains its function over a long period even under bad and sever environment such as the rolling process of the steel industrial machine.
Yoshiaki Naito
Cui Shu Tetsu
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