Steel sheet for hot stamping and hot-stamping formed body

A hot-stamping formed body consisting of, as a chemical composition, by mass %:

• C:
• more than 0.40% and 0.70% or less;
• Si:
• 0.010% to 1.30%;
• Mn:
• more than 0.60% and 3.00% or less;
• P:
• 0.100% or less;
• S:
• 0.0100% or less;
• N:
• 0.0130% or less;
• O:
• 0.0200% or less;
• Al:
• 0.0010% to 0.500%;
• Cr:
• 0.010% to 0.80%;
• Nb:
• 0% to 0.100%;
• Ti:
• 0% to 0.100%;
• B:
• 0% to 0.0100%;
• Mo:
• 0% to 1.00%;
• Co:
• 0% to 2.00%;
• Ni:
• 0% or more and less than 3.00%;
• Cu:
• 0% to 1.00%;
• V:
• 0% to 1.00%;
• W:
• 0% to 1.000%;
• Ca:
• 0% to 0.010%;
• Mg:
• 0% to 1.000%;
• REM:
• 0% to 1.000%;
• Sb:
• 0% to 1.000%;
• Zr:
• 0% to 1.000%;
• Sn:
• 0% to 1.000%;
• As:
• 0% to 0.100%;
• and
• a remainder of Fe and impurities,
• wherein the hot-stamping formed body has a microstructure in which an average grain size of prior austenite grains is 5 to 25 μm,
• a standard deviation of grain sizes of the prior austenite grains is 0.1 to 2.0 μm, and
• a tensile strength of the hot-stamping formed body is 2,200 MPa or more.

A steel sheet for hot stamping comprising, as a chemical composition, by mass %:

• C:
• more than 0.40% and 0.70% or less;
• Si:
• 0.010% to 1.30%;
• Mn:
• more than 0.60% and 3.00% or less;
• P:
• 0.100% or less;
• S:
• 0.0100% or less;
• N:
• 0.0130% or less;
• O:
• 0.0200% or less;
• Al:
• 0.0010% to 0.500%;
• Cr:
• 0.010% to 0.80%;
• Nb:
• 0% to 0.100%;
• Ti:
• 0% to 0.100%;
• B:
• 0% to 0.0100%;
• Mo:
• 0% to 1.00%;
• Co:
• 0% to 2.00%;
• Ni:
• 0% or more and less than 3.00%;
• Cu:
• 0% to 1.00%;
• V:
• 0% to 1.00%;
• W:
• 0% to 1.000%;
• Ca:
• 0% to 0.010%;
• Mg:
• 0% to 1.000%;
• REM:
• 0% to 1.000%;
• Sb:
• 0% to 1.000%;
• Zr:
• 0% to 1.000%;
• Sn:
• 0% to 1.000%;
• As:
• 0% to 0.100%;
• and
• a remainder of Fe and impurities,
• wherein the steel sheet for hot stamping has a microstructure in which Sα+SGB, which is a total of an area ratio Sα of ferrite and an area ratio SGB of a granular bainite, is 10% or more and less than 50%, and
• SGB/Sα, which is a ratio between the area ratio SGB of the granular bainite and the area ratio Sα of the ferrite, is 0.30 to 0.70.