Abstract: A high-strength steel sheet satisfies a predetermined chemical composition in which a content of martensite is 93% by volume or more, contents of ferrite, pearlite, and bainite are 2% by volume or less in total, and a content of retained austenite is 7% by volume or less, based on an entire metal structure, a number of laths in martensite measured by a cutting method in a total length of 300 ?m in an image of the metal structure observed under a scanning electron microscope is 240 or more, and a tensile strength of the high-strength steel sheet is 1470 MPa or more.

Abstract: A high-strength steel sheet satisfies a predetermined chemical composition in which a content of martensite is 93% by volume or more, contents of ferrite, pearlite, and bainite are 2% by volume or less in total, and a content of retained austenite is 7% by volume or less, based on an entire metal structure, a number of laths in martensite measured by a cutting method in a total length of 300 ?m in an image of the metal structure observed under a scanning electron microscope is 240 or more, and a tensile strength of the high-strength steel sheet is 1470 MPa or more.

Abstract: A steel plate for hot stamping contains, in % by mass, C: 0.25% or more and 0.4% or less, Si: 1.05% or more and 1.4% or less, Mn: 0% or more and 1.4% or less, Cr: 0.6% or more and 3.0% or less, P: 0% or more and 0.03% or less, S: 0% or more and 0.02% or less, Al: 0.01% or more and 1% or less, N: 0% or more and 0.01% or less, B: 0.0005% or more and 0.005% or less, Ti: 0.005% or more and 0.1% or less, and iron and inevitable impurities as remainder. This steel plate for hot stamping exhibits excellent hardness stability in addition to a balance between strength and toughness as a relational expression of [C]2/9[Si]+7/9[Mn]+8/9[Cr]?7/4>0 is satisfied.