NOVEL HOT STAMPING LINES & TOOLING FOR 6XXX & 7XXX ALUMINUM COMPONENTS

The research work has been carried out on the bumper of a Mercedes Benz E-Class to show the application for the automotive industry of this innovative technology in which Fagor Arrasate is a pioneer.

The replacement of parts and structures traditionally made of steel by others made of aluminum will reduce the weight of vehicles, which will cut down fuel consumption and emissions of polluting gases or increase autonomy in the case of electric vehicles.

In this regard, 6xxx and 7xxx aluminum alloys are emerging due to their lightweighting potential and high specific strength. Forming consists of solution heat treatment (SHT), quenching and age hardening. Forming is usually combined with the quenching phase inside the forming die in one go, using cooled tooling.

In order to optimize the hot stamping line, a wide variety of process parameters were studied, such as the effect of different SHT temperatures and times, different transfer times, pressing forces, cooling times, lubrication conditions and types of age hardening.

Tests, in which more than 150 parts were hot-formed from AA7075 and AA6082 aluminum alloys to optimize a wide range of parameters and configurations, have shown that it is possible to reduce the weight of the bumper by 40% without affecting its safety characteristics by using these hot-stamped aluminum alloys.