| 摘要 |
PROBLEM TO BE SOLVED: To provide a rolling device suppressing dispersion in the serviceable life in finished products and stably elongating the life and to provide its manufacturing method. SOLUTION: This rolling device is manufactured by sorting either one member of an inner member, an outer member, or a rolling body using an emission spectrophotometer so that it comprises a steel material wherein 600 pieces or less of oxide inclusions of a mean grain size of 3-30μm are included per 200mm<SP>2</SP>and a distribution ratio of the oxide inclusions of a mean grain size of 10μm or more is 15% or less; and by sorting it using a supersonic detector so that the square root length of all the oxide inclusions existing in a range from a track surface to a depth position intruding into 2% inside the diameter of the rolling body becomes 200μm or less. COPYRIGHT: (C)2004,JPO
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