| 摘要 |
PURPOSE:To improve the press formability of the cold rolled steel sheet for super deep drawing by executing the machining in the specified roughness on the surface of a work roll by a laser dulling machine and executing the machining in the specified roughness on the steel sheet surface by this work roll. CONSTITUTION:The aggregation of a small crater like recessed part and a ring like rise part of the outer edge thereof is executed on the surface of a rolling work roll by a laser dulling machine. The ratio Sm/d of the mean center distance Sm among the recessed parts thereof to the diameter D of the ring like rise part outer edge is taken 1.0-1.7 and the center line mean roughness Ra of the surface is 3mum. The machining that the center line mean roughness Ra becomes the roughness >=1.5mum is executed on the surface of the steel sheet by this work roll. Thus, the quality trouble of the sheet face can be eliminated. |
