ALUMINUM ALLOY ROLLED SHEET FOR FORMING EXCELLENT IN STRESS CORROSION CRACKING RESISTANCE AND ITS MANUFACTURE

摘要

PURPOSE: To provide an aluminum allay rolled sheet for forming excellent in strength and formability as well as stress corrosion cracking resistance on the base metal part and weld zone and suitable for an automotive body seat or the like and to provide its manufacturing method. ;CONSTITUTION: The objective rolled sheet has a componental compsn. fundamentally constituted of 3.0 to 7.0% Mg, 0.1 to 1.0% Zn, ≤0.1% Cu, ≤0.4% Fe and ≤0.2% Si, and the balance substantial Al, and, in which the average size of precipitates (β phases and T phases) caused by Mg or Zn is regulated to the range of 0.2 to 4.0μm. After the rolling, it is subjected to solution treatment of holding it to 280 to 580°C for ≤24hr at the maximum and executing cooling. As it is in the case the cooling rate of the solution annealing is ≤1°C/min, or, final annealing (precipitating treatment) of executing heating at 180 to 280°C for 30min to 24hr is applied to obtain the precipitating state.;COPYRIGHT: (C)1993,JPO&Japio