| 摘要 |
PURPOSE:To improve the commercial value and production yield of a cold rolled steel sheet by specifying a relation between peak heights from the centerline, an average peak height, and the number of peaks in a sectional curve of surface ruggedness of a dull surface of a cold rolled steel sheet. CONSTITUTION:A one surface of a cold rolled steel sheet is made to be bright and the other surface is made to be dull. In a sectional curve 1 of surface ruggedness, relation shown by the inequality I is met when a peak height to a centerline 3, an average peak height 4, and the number of peaks in a observation length are denoted by (hi), (h), and (n), respectively. Work rolls whose one is a bright roll and the other is a dull roll worked by high energy density beams are used and skin pass rolling is performed by an elongation percentage of >=0.3%. Hence, generation of lap and push-in flaws is prevented. |
