| 摘要 |
Provided is a high-strength, high-Young's modulus steel plate having a 780MPa or greater TS, a 205GPa or greater Young's modulus in the rolling direction and in a direction 45° relative to the rolling direction, a 220GPa or greater Young's modulus in the direction orthogonal to the rolling direction, a 1.05 or greater average r value, and a 2.03 or greater limit draw ratio (LDR). This high-strength, high-Young's modulus steel plate contains, in mass%, C:0.060-0.150%, Si:0.50-2.20%, Mn:1.00-3.00%, Nb:0.001-0.200% and V:0.001-0.200%, has a content of solid solution C (C*) that is calculated with a prescribed expression on the basis of the C, Nb and V content and satisfies expression (1) below, and has a microstructure having a ferrite area ratio of 20% or greater, a martensite area ratio of 5% or greater, a ferrite average crystal grain diameter of 20.0μm or less, and an inverse intensity ratio of γ-fibers to α-fibers of 1.00 or greater in each of the ferrite and martensite. 500 ≦ C* ≦ 1300... (1) Here, the unit of C* is mass [ppm]. |
