| 摘要 |
PURPOSE:To improve press formability regardless of surface roughness by determining the surface roughness pattern of a cold rolled steel sheet in such a manner that the regularity parameter expressed by the specific equation satisfies specific conditions. CONSTITUTION:The regularity parameter S expressing the regularity of the surface roughness of the steel expressed by the equation satisfies S<=0.25 in at least one direction in the surface roughness pattern of the cold rolled steel sheet. In the equation, Xi denotes the distance between the peaks of the projections one the surface of the steel sheet. The regular roughness pattern is provided to the surface of the steel sheet in the above-mentioned manner, by which the press formability is improved even with the steel sheet of the same material. The using range thereof is thus widened and the forming with high difficulty is made possible as well.
|
