| 摘要 |
PROBLEM TO BE SOLVED: To provide a cold rolled sheet steel having excellent chemical convertibility, especially even in an extra low carbon system, without being restricted by the composition the steel sheet.SOLUTION: In a cold rolled sheet steel in which oxides adhere onto the surface discontinuously so as to be distributed, when the ratio of the oxide area to a unit area of the cold rolled sheet steel surface in a plane view is defined as an oxide area ratio M(%), and the mean diameter of the oxides in a plane view is defined as an oxide mean diameter D(μm), M and D satisfy following formulas (1) and (2): 5≤M≤50 (1), 0.005×M≤D≤0.35 (2). The oxides may be, for example, oxides containing Si. |
