Patent ID: 6994760

Claim:
Method of producing a high-strength balanced Al—Mg—Si alloy product with an improved fatigue crack growth resistance and a low amount of intermetallics, comprising the steps of: a) casting an ingot with the following composition (in weight percent): Si: 0.75+14 1.3+11 Cu: 0.6+14 1.1 Mn: 0.2+14 0.8 Mg: 0.45+14 0.95 Fe: 0.01+14 0.3+11 Zr: +21 0.25 Cr: +21 0.25 Zn: +21 0.35 Ti: +21 0.25 V: +21 0.25 Hf: +21 0.25 impurities each less than 0.05 and less than 0.20 in total, balance aluminum, b) homogenizing the cast ingot with temperatures below 530° C., subsequently cooling with a trajectory down to a temperature below 100° C., c) pre-heating the homogenized ingot after casting for 4 to 30 hours with temperatures above 530° C. and 560° C., d) hot working the ingot and optionally cold working, e) solution heat treating, and f) quenching the worked product, wherein the amount of intermetallics or low melting incipient phases within the finally worked alloy product, according to the measured specific energy Delta H associated with the DSC signal, is below 1.5 J/g.