To achieve weight reduction in automobiles and to improve fuel economy, extremely crowned steel sheet (ECSS) has been developed. This ECSS reduces weight by about 3%/panel (0.3kg/panel). Hot coils with a mid-width thickness of 3.50mm and crown of 0.50mm have been rolled from slabs which are 165mm thick with a rectangular profile. Also, cold strip with thickness of 1.20mm , 0.90mm , 0.75mm and crowns of 0.145mm, 0.120mm, and 0.105mm respectively, has been successfully rolled.In the rolling of ECSS, two important points are the deformation of the cross sectional profile of the rolling stock and crown control to achieve proper flatness. The former should be taken care of in the upstream stands of hot strip mills, and the latter should be attended to in the downstream stands of hot strip mills, cold strip mills, and temper mills.On the other hand, the crown of the ECSS was restricted by the amount of work roll camber in the upstream stands of the hot strip mill. This was caused by contact between the backup roll and the work roll.
展开▼
