| 摘要 |
PURPOSE:To improve the bright reflectivity of a painted film on a steel sheet rolled by use of a roll by forming surface patterns consisting of assemblies of crater-like recesses and ring-shaped swelled part on a surface of the roll having a surface hardened layer being in a particular mutual relation. CONSTITUTION:Assembled patterns of small crater-like recesses 1 and ring- shaped swelled part 2 at the outer edge of the recesses 1 are formed by lasers on the surface of a roll 3 for cold rolling. A ratio Sm/D of an average center-to- center distance Sm of adjacent recesses 1 and a diameter D of the outside edge of the swelled part 2 and a value of Sm-D are brought in the range of 0.85-1.7 and a value less than 280 mum, respectively. Then, by light draft rolling on an annealed steel sheet 7 by use of a work roll 3 subjected to the dull working, the dull patterns of the roll 3 are transferred on the sheet 7 to form a rough surface on the surface of the sheet 7. The bright reflectivity tight adhesion of paint or enamel are obtained by the geometric patterns, that is, the surface roughness. |
