Cold-rolled steel sheet, coated steel sheet, method for manufacturing cold-rolled steel sheet, and method for manufacturing coated steel sheet

Abstract

Provided are a cold-rolled steel sheet which can preferably be used for manufacturing a high-strength galvanized steel sheet and methods for manufacturing the steel sheets. The cold-rolled steel sheet has a specified chemical composition, in which the Mn concentration in a surface layer of the steel sheet satisfies relational expression (1) and relational expression (2) below. 8≤(Cp/Cc)×Mn . . . (1) (Cmin/Cc)×Mn≤2.5 . . . (2) where Cp: maximum Mn concentration in a region within 0.5 μm of the surface of a steel sheet in the thickness direction; Cc: average Mn concentration in a region from a position located 5 μm from a surface of a steel sheet in the thickness direction to a position located 5 μm from an opposite surface in the thickness direction; Cmin: minimum Mn concentration in a region from 0.5 μm to 5 μm from the surface of a steel sheet in the thickness direction; and Mn: Mn content (mass %).

Dependencies are inferred from the claim text.