Hot-pressed steel sheet member, method of manufacturing the same, and steel sheet for hot pressing

1. A hot-pressed steel sheet member, comprising:

a chemical composition represented by, in mass %:

C: 0.10% to 0.34%;

Si: 0.5% to 2.0%;

Mn: 1.0% to 3.0%;

sol. Al: 0.001% to 1.0%;

P: 0.05% or less;

S: 0.01% or less;

N: 0.01% or less;

Ti: 0% to 0.20%;

Nb: 0% to 0.20%;

V: 0% to 0.20%;

Cr: 0% to 1.0%;

Mo: 0% to 1.0%;

Cu: 0% to 1.0%;

Ni: 0% to 1.0%;

Ca: 0% to 0.01%;

Mg: 0% to 0.01%;

REM: 0% to 0.01%;

Zr: 0% to 0.01%;

B: 0% to 0.01%;

Bi: 0% to 0.01%; and

balance: Fe and impurities; and

a steel structure in which:

an area ratio of ferrite in a surface layer portion ranging from a surface to 15 μm in depth is equal to or less than 1.20 times an area ratio of ferrite in an inner layer portion being a portion excluding the surface layer portion; and

the inner layer portion comprises a steel structure represented, in area %:

ferrite: 10% to 70%;

martensite: 30% to 90%; and

a total area ratio of ferrite and martensite: 90% to 100%,

wherein a concentration of Mn in the martensite is equal to or more than 1.20 times a concentration of Mn in the ferrite, in the inner layer portion, and

wherein a tensile strength of the hot-pressed steel sheet member is 980 MPa or more.

2. The hot-pressed steel sheet member according to claim 1 , wherein the chemical composition comprises one or more selected from the group consisting of, in mass %:

Ti: 0.003% to 0.20%;

Nb: 0.003% to 0.20%;

V: 0.003% to 0.20%;

Cr: 0.005% to 1.0%;

Mo: 0.005% to 1.0%;

Cu: 0.005% to 1.0%; and

Ni: 0.005% to 1.0%.

3. The hot-pressed steel sheet member according to claim 1 , wherein the chemical composition comprises one or more selected from the group consisting of, in mass %:

Ca: 0.0003% to 0.01%;

Mg: 0.0003% to 0.01%;

REM: 0.0003% to 0.01%; and

Zr: 0.0003% to 0.01%.

4. The hot-pressed steel sheet member according to claim 1 , wherein the chemical composition comprises, in mass %, B: 0.0003% to 0.01%.

5. The hot-pressed steel sheet member according to claim 1 , wherein the chemical composition comprises, in mass %, Bi: 0.0003% to 0.01%.