| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel sheet having improved wear resistance, fatigue properties or the like by examining a production process such as material designs and nitriding treatment methods with the practice of nitriding treatment as assumption, and performing nitriding treatment to a steel member, thus hardening its surface and further generating compressive stress. SOLUTION: The steel sheet is composed of a steel member having a composition in which the concentration of Cr is, by mass, 3 to 9%, the concentration of Ni is 5 to 12%, also, the (Cr+Ni) concentration is 10 to 15%, and further, the concentration of Mn is≤5%, and having a two phase structure of an austenitic phase and a martensitic phase, and in which a working-induced martensite phase is precipitated, the precipitation amount of the working-induced martensite phase is≥30% by volume, also, the ratio of the remaining austenite phase is 5 to 20% by volume, and further, a nitriding treatment layer is formed at the surface layer part. COPYRIGHT: (C)2011,JPO&INPIT
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