Cold Rolled Steel Sheet And Method For Manufacturing Same

Abstract: This cold-rolled steel sheet has a specified chemical composition, in which the metal structure of a t/4 part, which is a part located at a depth of 1/4 of the thickness t of the cold-rolled steel sheet from the surface of the cold-rolled steel sheet when observed in the thickness direction, contains, in % by volume, retained austenite in an amount of 2.5% to 10.0% inclusive, tempered martensite in an amount of 80.0% to 97.5% inclusive, ferrite and bainite in a total amount of 0.0% to 15.0% inclusive, and martensite in an amount of 0.0% to 3.0% inclusive, the amount of Si contained in the form of a solid solution in a surface part, which is a part located at a depth of 25 µm from the surface of the cold-rolled steel sheet when observed in the thickness direction, is 0.30% by mass to 1.50% by mass inclusive, and the volume ratio of ferrite is 0.0% to 20.0% inclusive and the density of ferrite crystal grains each having a grain diameter of 15 µm or more is 0 grain/mm2 to 3000 grains/mm2 inclusive in the metal structure.

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