PREPARATION OF HIGH TENSILE ALUMINUM ALLOY PLATE FOR FORMING

PURPOSE:To obtain a high tensile aluminum alloy plate of which the crystal grain is made fine and the forming processability is improved, by applying rapid heat treatment to a cold rolled plate comprising an Al-Cu-Mn-Mg alloy having a specific composition of which the Si and Fe amounts are limited while subjecting thus, heat treated alloy plate to perfect annealing treatment. CONSTITUTION:A cold rolled plate is fabricated from an Al-alloy having a composition consisting of, on a wt. basis, 3.5-5.0% Cu, 0.2-1.3% Mn, 1.2-1.8% Mg, 0.12% or less Si, 0.15% or less Fe and the remainder of Al and inevitable impurities. This cold rolled plate is rapidly heated at a speed of 2X10 deg.C/hr or more and heat treated at 350-450 deg.C for 5sec-30min. Subsequently, usual perfect annealing treatment is applied to the heat treated plate. By this method, a crystal grain is made fine and formability is improved and a high tensile aluminum alloy plate suitable for an airplane is obtained.