| 摘要 |
A hollow body from an aluminum alloy is prepared by a method of manufacturing a hollow body under pressure from an aluminum alloy, comprising the steps of: (1) preparing an alloy of a composition consisting of (by weight) 5.6</=Zn</=6.1, 2.0</=Mg</=2.4, 1.3</=Cu</=1.7, 0.15</=Cr</=0.25, Fe</=0.10, Fe+Si</=0.25, Mn</=0.04, Zr</=0.03, Ti</=0.04, with the remainder of the alloy being aluminum and impurities with the total amount of impurities being no more than 0.15 with the maximum amount of any given impurity being 0.05; (2) casting the alloy in the form of a billet; (3) hot extruding a billet at a temperature between 350 DEG and 450 DEG C. by the indirect process into the form of a case; (4) drawing out the resultant case hot then cold; (5) hot necking the drawn case between 350 DEG and 450 DEG C.; (6) solution annealing the hot necked case between 450 DEG and 490 DEG C. and quenching the case with water at a temperature below 40 DEG C.; and (7) two step tempering (type T73) the quenched case. |
