Rolling contact element steel and rolling bearing made thereof
AssigneeNippon Seiko Kabushiki Kaisha
InventorNobuaki Mitamura
Life of this patent
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Abstract
A rolling contact element steel has C: 0.2-0.6 wt %; Si: 0.5-2.0 wt %; Cr: 5.0-8.0 wt %; Mo: 3.0 wt % or less; Mn: 1.6 wt % or less; O: 12 ppm or less; and the balance of Fe and an inevitable impurity. A rolling bearing made of this steel will not soften even at high temperature. The dimensional stability at high temperature and wear-resistance of the steel are superior. The steel can produce a fine carbide without the need for a separate heat treatment. A rolling bearing has at least one of the races and the rolling element made of the steel, the steel being carburized or carbonitrided, then quenched and finally high-temperature tempered.
Claims4
A rolling bearing, comprising:
- races;
- and
- rolling elements, at least one of said races and said rolling elements being made of an alloy steel consisting essentially of:
- C:
- about 0.2-0.6 wt %;
- Si:
- about 0.5-2.0 wt %;
- Cr:
- about 5.0-8.0 wt %;
- Mo:
- not more than about 3.0 wt %;
- Mn:
- not more than about 1.6 wt %;
- O:
- not more than about 12 ppm;
- and the balance of Fe and any inevitable impurity, the at least one of said races and said rolling elements being carburized or carbonitrided, then quenched and then high-temperature tempered such that carbides are deposited in the surface layer of the at least one of said races and said rolling elements, the size of the carbide particles being about 0.5-1.0 .mu.m in diameter, and the content of the carbides being about 20-50 Vol %.
Dependencies are inferred from the claim text.