EXTREMELY THIN STEEL SHEET, HOT ROLLED STEEL SHEET FOR EXTREMELY THIN STEEL SHEET, AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To manufacture the extremely thin steel sheet for can, having uniform material and sheet thickness in the width direction of the sheet regardless of an extremely thin and wide width. ;SOLUTION: A slab is made to a sheet bar by rough rolling, the sheet bar is butted against a preceding sheet bar to join them, and the width tip part of the sheet bar is heated by an edge heater. Next, in at least three stands, continuous finish rolling is performed by pair cross roll rolling to produce a hot rolled steel strip with 950mm in sheet width or over, 0.5 to 2mm in sheet thickness and within ±40μm in crown. And, cold rolling, continuous annealing and skin pass rolling are applied to this hot rolled steel strip. According to circumstances, further a plating treatment is applied to the surface of this cold rolled steel strip. Consequently, the steel sheet with characteristics of 0.20mm in average sheet thickness or below, 950mm in sheet width or over, within ±4% of an average sheet thickness in fluctuation quantity of the sheet thickness in the sheet width direction in the range of 95% or over of the sheet width of the steel sheet, and within ±3 of averagehardness in the fluctuation quantity of hardness (HR30T) in the sheet width direction, is made.;COPYRIGHT: (C)1997,JPO