| 摘要 |
The purpose of the present invention is to overcome the problem of dimensional instability or peeling of a steel material by setting the hardness and residual austenite amount thereof to a specific range and numerically defining the relationship between the hardness and the residual austenite amount. The present invention is a roller bearing for a washing machine, characterized in that at least one of an inner race, an outer race, and a rolling element comprises a steel material having a specific composition, comprises steel in which the square root of the area of the largest oxide inclusion present in an area of 30,000 mm2 is 22-50 µm as predicted by extreme value statistics, and satisfies conditions (A) through (C) after quenching and tempering thereof. (A) The hardness after quenching and tempering is Hv715-811. (B) The residual austenite amount after quenching and tempering is 11-28 vol%. (C) The expression 810 ≤ [HV] + 4[γR] ≤ 871 is satisfied, where [HV] is the hardness after quenching and tempering, and [γR] is the residual austenite amount after quenching and tempering. |
