| 摘要 |
PURPOSE: To produce an aluminum alloy substrate for lithographic plate, suitable for electrochemical surface roughing treatment, by preparing an aluminum alloy sheet which consists of specific percentages of Fe, Si, and Al and in which resistivity at liquid nitrogen temp. is specified. CONSTITUTION: An ingot is prepared from an aluminum alloy material consisting of, by weight, >0-O.20% Fe, 0-0.13% Si, >=99.7% Al, and the balance inevitable impurity elements and then formed into a sheet excellent in degree of flatness by the ordinary method, by which the aluminum alloy substrate for lithographic plate having (3.50 to 5.50)×10<-6>Ω.mm resistivity at liquid nitrogen temp. can be produced. This substrate contains 0-<0.05wt.% Ti and 0-<0.05wt.% Cu and has >=14.0kg/mm<2> tensile strength and 1-8% elongation and also has >=10.5kg/mm<2> proof stress at the time when heat treatment is done under the conditions of 300 deg.C heating time and holding for 7min. By this method, the aluminum alloy substrate for lithographic plate, excellent in apptitude for surface roughing, can be obtained.
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