Steel Sheet And Method For Producing Same

Abstract: The present invention provides a steel sheet having an improved bendability post-plastic working, and also provides a method for producing this steel sheet. The steel sheet according to the present invention has a tensile strength of at least 980 MPa; has a prescribed chemical composition and a prescribed steel structure; and has, in the surface layer region of the steel sheet, a deboronized layer in which the B emission intensities B30, B140, and B150 —according to measurement in the depth direction from the steel sheet surface by radio frequency glow discharge optical emission spectroscopy at depth positions of 30 µm, 140 µm, and 150 µm from the steel sheet surface— satisfy B30/B150 < 0.90 and 0.90 = B140/B150 = 1.10. In addition, the C emission intensities C30, C140, and C150 for the surface layer region of the steel sheet —according to measurement in the depth direction from the steel sheet surface by radio frequency glow discharge optical emission spectroscopy at depth positions of 30 µm, 140 µm, and 150 µm from the steel sheet surface— satisfy C30/C150 = 0.5 and 0.90 = C140/C150 = 1.10.

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