Steel Sheet And Method For Manufacturing Same

Abstract: Provided are a steel plate and a method for manufacturing the same, the steel plate being characterized by having a prescribed chemical composition, and in that: the metal structure at the 1/4 thickness position, which is the range of 1/8 to 3/8 of the plate thickness of the steel plate in the plate thickness direction of the steel plate from the surface of the steel plate centered at the position at 1/4 of the plate thickness from the surface, contains, as area ratio, 0 to 60% ferrite and 0 to 3% retained austenite, with the remainder containing martensite and one or more materials selected from bainite, pearlite, and cementite; the ferrite fraction in the range up to 2 µm from the surface of the steel plate in the plate thickness direction of the steel plate is 95% or above; the in-plane average particle diameter of the ferrite in the in-plane direction is 2.0 µm or below; the ferrite fraction in the range of 5 to 20 µm from the surface of the steel plate in the plate thickness direction of the steel plate is smaller than 90%; and the tensile strength is 950 MPa or higher.

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