| 摘要 |
PURPOSE:To prevent galvanic corrosion of mild steel sheets and to secure strength formability sufficient to be used as can lid material, by incorporating specific amounts of Mg, Si, Fe, Mn, and Cu to Al and by specifying the natural electrode potential of the resulting alloy. CONSTITUTION:An ingot of an Al alloy consisting of, by weight, 0.40-2.0% Mg, 0.05-0.10% Si, 0.05-0.50% Fe, 0.30-1.5% Mn, 0.10-1.0% Cu, and the balance Al is prepared. This ingot is subjected to homogenizing treatment, to hot rolling, and then to cold rolling to be formed into a sheet having a thickness >=about 1.2 times as much as the final thickness, which is heated at about 300-580 deg.C for <=about 3hr to undergo heat treatment. Then this alloy sheet is subjected to final cold rolling and the natural electrode potential in a 0.1% solution of salt (25 deg.C) is regulated to -700--630mV by use of AgLl as a reference electrode. This Al alloy sheet is minimized in galvanic corrosion due to the contact potential difference with mild steel sheets, so that it is suitable for use as lid material for steel cans for salt-containing food and drink.
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