| 摘要 |
PURPOSE:To make better the extrudability of the title Al alloy, to eliminate its internal strain and to provide it with high mechanical strength by specifying the content of Zn, Mg, Cu, Cr, Zr and Ti in an Al alloy. CONSTITUTION:An Al alloy for a masking frame of a projective exposure apparatus is formed with the compsn. contg., by weight, 5-7% Zn, 1.0-1.5% Mg and 0.05-0.8% Cu, contg. one or two kinds of 0.03-0.1% Cr and 0.05-0.3% Zr, furthermore contg. 0.001-0.1% Ti and the balance consisting of Al with inevitable impurities. By this compsn., its extrudability is made better and the manufacturing efficiency is made high. Since there is no need for quenching, the alloy has less generation of internal strain and has no generation of deformation and wrinkles even if thinly machined. The alloy furthermore has good alumite characteristics and therefore has the characteristics of good corrosion resistance, etc. |
