| 摘要 |
In a hot stamped steel, when [C] represents an amount of C (mass%), [Si] represents an amount of Si (mass%), and [Mn] represents an amount of Mn (mass%), an expression of 5 × [Si] + [Mn]) / [C] > 10 is satisfied, a metallographic structure includes 80% or more of a martensite in an area fraction, and optionally, further includes one or more of 10% or less of a pearlite in an area fraction, 5% or less of a retained austenite in a volume ratio, 20% or less of a ferrite in an area fraction, and less than 20% of a bainite in an area fraction, TS × » which is a product of TS that is a tensile strength and » that is a hole expansion ratio is 50000MPa·% or more, and a hardness of the martensite measured with a nanoindenter satisfies H2 / H1 <1.10 and ÃHM < 20. |
