| 摘要 |
PURPOSE:To improve the sharpness of a product by forming microscopically flat trapezoidal peak parts, valley parts enclosing said parts and intermediate flat parts to the surface of a steel sheet having specific roughness. CONSTITUTION:While work rolls 3 for temper rolling are rotated, laser pulses are projected one after another to the roll surface to form crater-shaped recesses 1 and flange-shaped build-up parts 2 on the roll 3 surface. The ratio Sm/d of the average distance Sm between the recesses 2 and the outside diameter D of the build-up parts 2 is specified in a 1.7-3.0 range and the value of Sm-D is specified to <=450mum. The steel sheet 7 having 0.3-2.0 m center line average height Ra of the surface is subjected to the temper rolling at <=0.3% elongation lambdaby using such rolls 3, by which the steel sheet for painting having the surface shape expressed by the equation I is obtd. Since the steel sheet has the surface shape to decrease irregular reflection of light, the sharpness of the product is improved. |
