| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-strength hot-rolled steel plate superior in the balance of strength, ductility and work hardening characteristics. SOLUTION: The high-strength hot-rolled steel plate comprises, by mass% (hereinafter the same about components), 0.06-0.23% C, 0.5-2.5% Si, 0.5-2.5% Mn, 0.03-0.10% Nb and/or 0.1-1.0% Mo, and the balance iron with unavoidable impurities; and has a metallographic structure which includes, by an area rate (hereinafter the same about the metallographic structure), 5-20% retained austenite, 20% or more polygonal ferrite and 30% or more bainitic ferrite, while satisfying 60% or more polygonal ferrite and bainitic ferrite in total. COPYRIGHT: (C)2005,JPO&NCIPI
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