| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-strength hot-rolled steel plate which has a small in-plane anisotropy and superior hole expandability, and to provide a manufacturing method therefor. Ž<P>SOLUTION: The hot-rolled steel plate superior in hole expandability comprises, by mass%, 0.005 to 0.150% C, 2.50% or less Si, 0.10 to 3.00% Mn, 0.150% or less P, 0.0150% or less S, 0.150% or less Al, 0.0100% or less N, 0.005 to 0.07% Nb, and the balance Fe with unavoidable impurities; has a structure formed of ferrite, or ferrite and bainite, while the ferrite has a grain diameter of 30 μm or smaller; has a mean value of random X-ray intensity ratios of crystal grains having orientation groups of ä100}<011> to ä223}<110> in an amount of 4.0 or less; and has a mean value of random X-ray intensity ratios of crystal grains having orientations of ä554}<225>, ä111}<112> and ä111}<110> in an amount of 4.5 or less, in a plate plane at 1/2 of the plate thickness. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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