| 摘要 |
PURPOSE:To provide the steel sheet for painting which is greatly improved in press workability by regulating the surface roughness patterns of the steel sheet. CONSTITUTION:This steel sheet for painting which has the excellent press formability is formed by providing many microrecessed parts having circular, elliptical and polygonal or other shapes on the surface of the steel sheet. The shapes of these recessed parts are so determined that the diameter d satisfies a range of 50 to 200mum, the depth h of the recessed parts 2 to 16mum, and the volume of the recessed parts 1X10<3> to 1X10<6>mum range. The center-to-center distance (p1) between the adjacent recessed parts in a rolling direction is specified to 1.0 to 1.5d and the center-to-center distance (p2) between the arrays of the rolling direction arrays to 0.1 to 1.5d. The cold rolled steel sheet for painting having the press formability and the high brightness after painting in combination is produced. The roll life is greatly improved by controlling the shapes of chromium projections. |
