| 摘要 |
PURPOSE:To improve the brightness of a steel sheet for painting by forming dull spots on a work roll by high energy beam irradiation meeting specific requirements and forming dull spot train titled at a prescribed deviation angle to both the orthogonal direction and the rolling direction on the steel sheet surface. CONSTITUTION:Transferable dull spots are formed on the surface of a work roll by shifting high energy beams such as laser beams in many places on the roll surface. In that time, the number of irradiations Q of beams per unit time is controlled based on a set pinch SmLo between adjacent dull spots in the roll peripheral direction so as to meet the inequality I. Then, a steel sheet for painting is rolled by use of the spotted work roll to correctly transfer the roll dull spots onto the sheet surface. In that case, the central line of adjacent dull spots has both deviation angles of alpha and beta tilting to the sheet rolling direction and to the orthogonal direction to the rolling direction and being set to be <=20 deg.. Hence, the brightness of the sheet is remarkably improved. |
