摘要 |
In a rolling shaft relatively rolling with respect to rolling members provided in a radial needle roller bearing, the rolling shaft is composed of a steel containing 0.5 to 1.2 wt % carbon and is provided with a surface layer 3a containing 0.05 to 0.4 wt % nitrogen, having Vickers hardness being Hv650 or more through a high frequency quenching performed thereto and a residual austenite being 15 to 40 vol %, and a core portion of the rolling shaft contains 0 vol % of the residual austenite.
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