| 摘要 |
PURPOSE:To produce an Al alloy composite plate having excellent corrosion resistance by molding the composite plate by using a skin material and core each contg. specific ratios of Mg, Si, Mn, Cu and Fe among which Cu content is regulated with specific inequalities and using an Al intermediate layer having high purity. CONSTITUTION:The composite plate is formed by using the skin material of the Al alloy contg., by weight, 0.4-2.0% Mg, 0.05-0.15% Si, 0.30-1.5% Mn, 0.10-0.50% Cu, 0.05-0.50% Fe and the balance consisting substantially of Al, the Al intermediate layer having >=99.5% purity and the core of the Al alloy contg. 0.4-2.0% Mg, 0.05-0.15% Si, 0.3-1.5% Mn, 0.50-1.5% Cu, 0.05-0.50% Fe and the balance consisting substantially of Al. At this time, the Cu content is regulated in such a manner that 30<=92(X1<1/2>-X2<1/2>)<=100 is satisfied where the Cu content in the core is denoted by X1 and that in the skin material by X2. By this method, the pitting potential difference between the core and skin material in 1.0% saline soln. is controlled to provide 30-100mV, and the corrosion resistant Al alloy composite plate suitable as a lid material is obtd.
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