Patent ID: 7763128

Claim:
A process for manufacturing a machined metal part, comprising: a) preparing a metal sheet or plate comprising a heat treatable aluminum alloy by a process comprising: a1) casting a rolling ingot, optionally followed by homogenisation, a2) conducting at least one hot or cold rolling operation, optionally separated by at least one re-heating operation, to obtain said sheet or plate, a3) conducting at least one cutting and/or finishing operation, b) pre-machining said sheet or plate on one or both sides thereof to form pre-machined stock of a targeted shape consisting of one or more machined channels at least 50.5 mm deep, and wherein said shape is approximately constant over the length of the sheet or plate, wherein a length of between about 50 mm and about 1,000 mm, at both ends of said sheet or plate does not comprise any profile and is of approximately constant thickness, and wherein at least one side of said stock is flat, c) solution heat treating said pre-machined stock, d) quenching said pre-machined stock, e) controlled stretching of said pre-machined stock, wherein said one or more machined channels minimize uncontrolled distortion of said stock and increases fracture toughness of said metal part above the fracture toughness of what would be obtained without including said shape consisting of one or more machined channels therein, and after said controlled stretching optionally conducting one of the following: f) aging, and/or g) cutting.