Aluminum alloy sheet for lithographic printing plate

Abstract

The present invention provides an aluminum alloy sheet for a lithographic printing plate which allows pits to be uniformly formed by electrochemical roughening, and excels in strength and heat softening resistance. The aluminum alloy sheet for a lithographic printing plate includes 0.1-0.3% of Mg, more than 0.05%, but 0.5% or less of Zn, 0.2-0.6% of Fe, 0.03-0.15% of Si, 0.02% or less of Cu, and 0.003-0.05% of Ti, the remainder being Al and impurities. The aluminum alloy sheet may include more than 0.05%, but 0.3% or less of Mn.

1 . An aluminum alloy sheet for a lithographic printing plate, comprising 0.1-0.3% of Mg, more than 0.05%, but 0.5% or less of Zn, 0.2-0.6% of Fe, 0.03-0.15% of Si, 0.02% or less (excluding 0%; hereinafter the same) of Cu, and 0.003-0.05% of Ti, the remainder being Al and impurities.  
     
     
         2 . An aluminum alloy sheet for a lithographic printing plate, comprising 0.1-0.3% of Mg, more than 0.05%, but 0.5% or less of Zn, more than 0.05, but 0.3% or less of Mn, 0.2-0.6% of Fe, 0.03-0.15% of Si, 0.02% or less of Cu, and 0.003-0.05% of Ti, the remainder being Al and impurities.  
     
     
         3 . The aluminum alloy sheet for a lithographic printing plate according to  claim 1  or  2 , wherein the Mg content and the Zn content satisfy a relationship expressed by 0.4×Zn %≦Mg %≦4×Zn %.