| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel having the superior rolling fatigue life used in parts for machinery, by employing an index other than the oxide of a conventional index. SOLUTION: The steel having the superior rolling fatigue life used in the parts for machinery is a steel for a machine structure or machine parts such as bearing steel, to which a surface hardness of 58 HRC or higher is given when the steel is used in the machine parts, wherein inclusions of sulfides contained in the steel have a predicted value of the maximum√area for the maximum diameter in 30,000 mm<SP>2</SP>in an amount of 40μm or less, which is calculated by applying statistics of extremes to maximum diameters of non-metallic inclusions in sections of each 100 mm<SP>2</SP>measured at 30 spots in the steel material. COPYRIGHT: (C)2006,JPO&NCIPI
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