| 摘要 |
PURPOSE:To obviate the generation of the residual dull trace after coating and to improve appearance by specifying the microscopic profile of the surface of the steel sheet. CONSTITUTION:The center line average roughness Ra on the surface of at least either of the front and rear surface of the steel sheet is ranged within 0.3 to 2.0mum and the microscopic profile constituting the surface roughness is constituted of trapezoidal peak parts and groove-shaped valley parts and intermediate flat parts. The following formulas are satisfie when the average distance between the centers of the adjacent peak parts 1, 1 is designated as Sm, the average diameter of the outer lines of the valley part as D, the average diameter of the flat peak surface 1 of the valley part as d0, the height between the peak surface of the peak part and the bottom of the valley part as (l), and the ratio at which the sum of the areas of the flat peak surface of the park part and the flat surface of the intermediate flat part occupies in the total area as eta%: 0.5<=Sm/D<=2.0, Sm-D<=300mum, d0<=500mum, 1mum<=l<=10mum, 20%<=eta<=85%. |
