Method of producing aluminum alloy sheet for lithographic printing plate

Abstract

A method of producing an aluminum alloy sheet for a lithographic printing plate includes homogenizing an ingot of an aluminum alloy at 500 to 610° C. for one hour or more, the aluminum alloy containing 0.05 to 1.5% of Mg, 0.1 to 0.7% of Fe, 0.03 to 0.15% of Si, 0.0001 to 0.10% of Cu, and 0.0001 to 0.1% of Ti, with the balance being aluminum and unavoidable impurities, subjecting the homogenized product to rough hot rolling, a start temperature of the rough hot rolling being 430 to 500° C. and a finish temperature of the rough hot rolling being 400° C. or more, holding the product subjected to the rough hot rolling for 60 to 300 seconds after completion of the rough hot rolling to recrystallize the surface of the product, subjecting the resulting product to finish hot rolling that is finished at 320 to 370° C., and winding up the resulting product in the shape of a coil to obtain a hot-rolled product having a surface with an average recrystallized grain size in a direction perpendicular to a rolling direction of 50 μm or less. The aluminum alloy may contain 2 to 30 ppm of Pb.

1 . A method of producing an aluminum alloy sheet for a lithographic printing plate comprising homogenizing an ingot of an aluminum alloy at 500 to 610° C. for one hour or more, the aluminum alloy comprising 0.05 to 1.5% (mass %; hereinafter the same) of Mg, 0.1 to 0.7% of Fe, 0.03 to 0.15% of Si, 0.0001 to 0.10% of Cu, and 0.0001 to 0.1% of Ti, with the balance being aluminum and unavoidable impurities, subjecting the homogenized product to rough hot rolling, a start temperature of the rough hot rolling being 430 to 500° C. and a finish temperature of the rough hot rolling being 400° C. or more, holding the product subjected to the rough hot rolling for 60 to 300 seconds after completion of the rough hot rolling to recrystallize the surface of the product, subjecting the resulting product to finish hot rolling that is finished at 320 to 370° C., and winding up the resulting product in the shape of a coil to obtain a hot-rolled product having a surface with an average recrystallized grain size in a direction perpendicular to a rolling direction of 50 μm or less. 
   
   
       2 . The method according to  claim 1 , wherein the aluminum alloy further comprises 2 to 30 ppm of Pb. 
   
   
       3 . The method according to  claim 1 , the method comprising subjecting the hot-rolled product to only cold rolling to obtain a sheet material having a specific thickness.