| 摘要 |
PROBLEM TO BE SOLVED: To produce a high strength alloy for a structural material excellent in extrudability by setting components in an Al-Zn-Mg alloy contg. specified amounts of Zn, Mg, Cu, Si, Fe, Zr, Ti and B so as to regulate its melting starting temp. to specified value and regulating Al-Zr compounds precipitated in the process of homogenizing treatment in the ingot to specified size. SOLUTION: This Al-Zn-Mg alloy is the one contg., by weight, 6 to 7% Zn, 0.9 to 1.3% Mg, 0.1 to 0.4% Cu, 0.05 to 0.2% Si, 0.1 to 0.4% Fe, 0.05 to 0.25% Zr, 0.005 to 0.1% Ti and 0.001 to 0.01% B. The components are set so as to regulate the melting starting temp. T to >=595 deg.C. The temp. T ( deg.C) is defined by 651-4.5×%Zn-17×%Mg-18×%Cu. The size of Al-Zr compounds precipitated in the process of homogenizing treatment in the ingot is regulated to <=0.05μm.
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