Process for producing aluminum alloy substrate for lithographic printing plate

Abstract

A process for producing an aluminum alloy substrate for a lithographic printing plate is provided, wherein an excellent grained surface can be realized even when the heat treatment time and alkali etching are shortened. The method includes the steps of preparing an ingot composed of specific ranges of Fe, Si, Cu, Ti, B, and unavoidable impurities; subjecting the ingot to a homogenization treatment composed of the first stage of holding at 510° C. to 560° C. for 30 minutes to 2 hours and the latter stage of holding at 460° C. to 500° C. for 30 minutes to 2 hours; starting hot rolling, followed by finishing at 360° C. or more; conducting cold rolling; conducting intermediate annealing at a heating temperature of X° C. for a holding time of Y sec in an inert gas atmosphere, where X is 400° C. to 620° C. and Y≧2×10 8 ×exp(−0.0284X) is satisfied; and conducting final cold rolling.

1 . A process for producing an aluminum alloy substrate for a lithographic printing plate, the process comprising the steps of: 
 preparing an aluminum alloy ingot having a JIS 1000 series composition;    subjecting the aluminum alloy ingot to a homogenization treatment comprising the first stage of holding at 510° C. to 560° C. for 30 minutes to 2 hours and the latter stage of holding at 460° C. to 500° C. for 30 minutes to 2 hours;    starting hot rolling and, thereafter, finishing the hot rolling at a temperature of 360° C. or more;    conducting cold rolling;    conducting intermediate annealing at a heating temperature of X° C. for a holding time of Y sec in an inert gas atmosphere, where X is 400° C. to 620° C. and Y≧2×10 8 ×exp(−0.0284X) is satisfied; and    conducting final cold rolling.    
   
   
       2 . The process for producing an aluminum alloy substrate for a lithographic printing plate according to  claim 1 , wherein the aluminum alloy ingot having a composition comprising: 
 0.1 to 0.50 percent by weight of Fe;    0.03 to 0.30 percent by weight of Si;    0.002 to 0.040 percent by weight of Cu;    0.01 to 0.05 percent by weight of Ti;    0.0001 to 0.02 percent by weight of B; and    the balance of aluminum and unavoidable impurities.