Process for manufacturing a strip of aluminium alloy for lithographic printing plates

A lithographic printing plate with electrolytically roughened surface, that has been manufactured as a strip using a process comprising

• (a) continuously casting the alloy as a strip in the gap between the cooled rolls of a strip-casting machine to a thickness of at most 3 mm, the continuous casting forming a cast strip having very fine, intermetallic particles in high density and having a small grain size in the regions close to the surface of the cast strip, and, in order to prevent coarsening of the grains, no further heat is applied to the cast strip which has been solidified in the roll gap between steps (a) and (b), and there is no annealing between steps (a) and (b);
• (b) cold rolling the cast strip so that the advantageous grain microstructure in the surface regions arising from rapid solidification is retained to final thickness with a thickness reduction of at least 90 percent, the cast strip not having any further heat applied to it until after the final thickness has been attained;
• and
• (c) electrolytically etching the cast strip in an HNO3 electrolyte, to roughen etched surface of the cast strip to provide the lithographic printing plate, said lithographic printing plate exhibits an improved etched structure for the same energy consumption compared to that of conventionally-produced lithographic printing plates.

A lithographic printing plate with electrolytically roughened surface, that has been manufactured as a strip using the process comprising

• (a) continuously casting the alloy as a strip in the gap between the cooled rolls of a strip-casting machine to a thickness of at most 3 mm, the continuous casting forming a cast strip having very fine, intermetallic particles in high density and having a small grain size in the regions close to the surface of the cast strip, and, in order to prevent coarsening of the grains, no further heat is applied to the cast strip which has been solidified in the roll gap between steps (a) and (b);
• (b) cold rolling the cast strip so that the advantageous grain microstructure in the surface regions arising from rapid solidification is retained to final thickness with a thickness reduction of at least 90 percent, the cast strip not having any further heat applied to it until after the final thickness has been attained;
• and
• (c) stoving a photosensitive coating on the cast strip to provide the lithographic printing plate, said lithographic printing plate exhibits higher strength than a conventionally-produced lithographic printing plate.

A lithographic printing plate with electrolytically roughened surface, that has been manufactured as a strip using the process comprising:

• (a) continuously casting the alloy as a strip in the gap between the cooled rolls of a strip-casting machine to a thickness of at most 3 mm, the continuous casting forming a cast strip having very fine, intermetallic particles in high density and having a small grain size in the regions close to the surface of the cast strip, and, in order to prevent coarsening of the grains, no further heat is applied to the cast strip which has been solidified in the roll gap between steps (a) and (b) and there is no annealing between steps (a) and (b);
• (b) cold rolling the cast strip so that the advantageous grain microstructure in the surface regions arising from rapid solidification is retained to final thickness with a thickness reduction of at least 90 percent, the cast strip not having any further heat applied to it until after the final thickness has been attained;
• and
• (c) stoving a photosensitive coating on the cast strip to provide the lithographic printing plate, said lithographic printing plate exhibits higher strength than a conventionally-produced lithographic printing plate.