Ford Motor Company
Artificial aging of strained sheet metal for strength uniformity

Abstract:

Methods of heat treating aluminum alloys are disclosed. The method may include forming a sheet of solution heat-treated, quenched, and aged 6xxx series aluminum having a sheet average yield strength of at least 100 MPa into a component. The component may then be attached to an assembly and at least a portion of the assembly may be painted. The method may then include heat treating the assembly to cure the paint and to increase a component average yield to at least 240 MPa. In another embodiment, the method may include progressively forging a sheet of T4-tempered 6xxx series aluminum into a component using multiple dies and artificially aging the component at 210.degree. C. to 240.degree. C. for 20 to 40 minutes to a component average yield strength of at least 300 MPa. The methods may reduce component cycle time and may reduce strength gradients within the component.