Method of manufacturing natural aging retardated aluminum alloy sheet.

摘要

Disclosed is a method manufacturing an aluminum alloy sheet comprising preparing an aluminum alloy ingot essentially consisting of 1.5 to 3.5% by weight of Mg, 0.3 to 1.0% by weight of Cu, 0.05 to 0.6% by weight of Si, and a balance of A l , in which the ratio of Mg/Cu is in the range of 2 to 7, homogenizing the ingot in one step or in multiple steps, performed at a temperature within a range of 400 to 580 DEG C, preparing an alloy sheet having a desired sheet thickness by subjecting the ingot to a hot rolling and a cold rolling, subjecting the alloy sheet to heat treatment including heating the sheet up to a range of 500 to 580 DEG C at a heating rate of 3 DEG C/sec. or more, keeping it for 0 to 60 seconds at the temperature reached, and cooling it to 100 DEG C or less at a looking rate of 2 DEG C/sec. or more, and keeping the alloy sheet at a temperature within a range of 180 to 300 DEG C for 3 to 60 seconds. Thus, a natural aging-retardated aluminum alloy sheet is obtained. <IMAGE>