Patent ID: 7901522

Claim:
Process for manufacturing plates having a thickness up to 300 mm out of an aluminium alloy comprising the steps of: (a) continuous casting the aluminium alloy comprising 4.6 to 5.2 wt. % Zn, 2.6 to 3.0 wt. % Mg, 0.1 to 0.2 wt. % Cu, 0.05 to 0.2 wt. % Zr, max. 0.05 wt. % Mn, max. 0.05 wt. % Cr, max. 0.15 wt. % Fe, max. 0.15 wt. % Si, max. 0.10 wt. % Ti, as an ingot having a thickness of greater than 300 mm; (b) heating the ingot at a maximum heating rate of 20° C./h between the temperature range of 170 and 410° C. to a final temperature of between 470 to 490° C.; (c) homogenising the heated ingot for an interval of 10 to 14 h at the final temperature range of 470 to 490° C.; (d) hot rolling the homogenised ingot to plate having a thickness of up to 300 mm; (e) cooling the plate from a temperature of 400 to 410° C. to a temperature of less than 100° C.; and (f) artificially age-hardening the plate.