| 摘要 |
PROBLEM TO BE SOLVED: To obtain an Al alloy sheet for a planographic printing plate having excellent uniformity of appearance after surface roughness treatment. SOLUTION: The Al alloy sheet for the planographic printing plate is composed of an Al alloy containing 0.1 to 0.5% FeO, 0.05 to 0.20% SiO, 0.005 to 0.07% CuO, and the balance Al, in which the cube surface bearing density share on the sheet surface right after recrystallization is≥10%; the crystal grain average surface area of the product sheet is≤0.1mm<SP>2</SP>and the average length perpendicular to the rolling direction of the crystal grains is 1,300μm. The Al alloy sheet for the planographic printing plate is≤100μm. The average length perpendicular to the rolling direction of the crystal grains is≤100μm. As the manufacturing method, the rolling reduction of finish rolling is so regulated that the ratio of rough rolling finish sheet thickness and finish rolling finish sheet thickness attains≥10 and hot rolling is performed at a rolling finish sheet thickness 1.2 to 4.0 mm, and a rolling finish temperature 300 to 360°C to induce recrystallation at the time of subjecting an ingot of the Al alloy to hot rolling (rough rolling + finish rolling), and the time right after the finish rolling before the ingot is cooled down to <300°C is regulated within 4 hours and thereafter, the sheet is finished to a product sheet thickness by cold rolling without being subjected to intermediate annealing. COPYRIGHT: (C)2007,JPO&INPIT
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