| 摘要 |
PURPOSE:To generate cracks over plural directions in a scale layer of the surface of a steel sheet, by providing plural bending rolls and broad-side bending rolls which are brought into rolling contact with the inside and outside surfaces of the steel sheet to a titled device, respectively, and providing bending strains to the sheet in its longitudinal and lateral directions, respectively. CONSTITUTION:Bending rolls 36, 38 are arranged between guide rolls 32, 34 of a steel sheet 10, respectively, and broadside bending rolls 48, 50 are provided to the spaces between guide a roll 40 and pinch rolls 42 and between a guide roll 44 and pinch rolls 46, respectively. The bending rolls 36, 38 are flat rolls and give longitudinal strains warping into L-shape to the sheet 10, respectively. Further, the broadside bending rolls 48, 50 are formed respectively into a large crown shape with a radius of curvature of about 200-800mm. and incorporate a large number of idle rolls 64 in its outer surface. In addition, are pair of pressing rolls 52, 54 are provided to the rolls 52, 54 respectively so that the rolls 52, 54 are respectively in rolling contact with the sheet 10 sandwiched between the rolls 52, 54 and 48, 50 respectively to give bending strains warping to C-shape to the sheet 10. In this way, cracks in the random directions are generated in a scale layer. |
