Adapted Mechanical Properties for Improved Formability of Aluminum Blanks by Local Induction Heating 2003-01-2750

In this paper a novel process sequence consisting of local induction heating followed by deep drawing of a precipitation hardenable aluminum alloy is presented and compared with conventional processing. Using an induction heating system, it is possible to change the mechanical properties of the 6xxx-series in a restricted area by influencing the precipitation structure. Hardness measurements and tensile tests characterize the conversion from the stable naturally aged condition T4 to reversible solution heat-treated conditions of AA6016 as function of temperature and time. This effect leads to a reduction of flow stress, which is used to design an initial material property distribution adapted for the subsequent deep drawing process. A process characterization study provides detailed information concerning induction heating parameters, to improve the deep drawing of cylindrical cups, which results in a decisive increase of the limiting drawing ratio. Accompanying the experimental investigations, a finite element analysis approach is realized as a process design and optimization tool.