| 摘要 |
PURPOSE:To obtain a steel sheet having excellent brightness and workability by regularly arranging ruggedness having specific roughness to the surface on one side of the steel sheet and specifying the area of said recesses and the spacings between the adjacent recesses within adequate ranges. CONSTITUTION:The recesses 1, 1', 1''... having 5-15mum Rmax are aregularly arranged on the surface on at least one side of the steel sheet. The relation between the area A of a piece of such recesses 1... and the spacing l between the respective adjacent recesses 1, 1', 1''... is determined to satisfy the two condition equations: 1.0X10<-3>mm<2=A<=40X10<-3>mm<2>, A<0.5>/4<=l<=4A<0.5>. The parts except the above-mentioned recesses 1... on the surface of the steel sheet are flat parts 2 having the roughness of an ordinary bright steel sheet, i.e., <=3.0mum Rmax. The above-mentioned recesses 1... can be formed by rolling the steel sheet with rolls subjected to surface working with prescribed rugged patterns by a laser beam. The steel sheet provided with both of the brightness equiv. to the brightness of the conventional bright steel plate and the workability equiv. to the workability of a dull matte steel sheet is thereby obtd.
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