| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel component using a cold rolled steel sheet which is more improved in fatigue strength than heretofore. SOLUTION: In the steel component produced using a cold rolled steel sheet, at least a part has a hardened structure by quenching, and the old austenite grain size in the hardened structure is controlled to≤12μm. COPYRIGHT: (C)2007,JPO&INPIT
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