Process for producing aluminum alloy substrate for lithographic printing plate

Abstract

In order to produce an aluminum alloy substrate for a lithographic printing plate wherein grain structure refining and homogenizing are promoted, and the uniformity of the appearance of the grained surface is particularly improved, the process of the present invention comprises the steps of: homogenizing an aluminum alloy ingot comprising 0.10 to 0.40 wt % of Fe, 0.03 to 0.30 wt % of Si, 0.004 to 0.050 wt % of Cu, 0.01 to 0.05 wt % of Ti, 0.0001 to 0.02 wt % of B and the balance of Al and unavoidable impurities, at temperatures of 350 to 480° C., successively hot-rolling the ingot with a plurality of passes in such a manner that the aluminum alloy is not recrystallized prior to the hot rolling of the final pass and recrystallized at least in the surface layer of the hot-rolled plate by only the hot rolling thereof to form a recrystallized structure having an average recrystallized grain size of less than 50 μm in a direction normal to the rolling direction, and cold-rolling the hot-rolled plate. The reduction of the plate in the hot rolling of the final pass is desirably at least 55%.

Dependencies are inferred from the claim text.