Hot-pressed steel sheet member, method of manufacturing the same, and steel sheet for hot pressing
Abstract:
A hot-pressed steel sheet member includes a specific chemical composition and further includes 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 contains 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%. 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 a tensile strength of the hot-pressed steel sheet member is 980 MPa or more.
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