Weight halved: Lightweight automotive technology with magnesium
Prototyp for BMW 3er- Serie
At the first TeMaKplus workshop, BMW M GmbH presented a magnesium rear seat backrest for the BMW 3-series. Stemming from an advance engineering project, the rear seat backrest is a 60/40 split folding design. Weighing only 5.45 kilograms, the magnesium backrest is over 50 percent lighter than a conventional steel backrest weighing around 11.5 kilograms.
Design and engineering of the magnesium backrest as well as subsequent prototype production was carried out by Karosserie Werke Dresden GmbH (KWD) headed by Dr. Jens Ullrich.
The rear seat backrest is a stamped and welded design similar to the conventional assembly. The magnesium sheet used for it was supplied in thicknesses of 1.5 mm and 2 mm by ThyssenKrupp MgF Magnesium Flachprodukte GmbH, a subsidiary of ThyssenKrupp Steel Europe AG. The magnesium backrest has been proven to meet statutory crash-related requirements.
The main crash performance requirement is specified in the regulation ECE R17. It focuses on occupant protection against cargo in the luggage compartment in the event of a collision (protection against cargo). In the crash test, which was also carried out for the magnesium backrest, two 300 mm square test blocks each weighing 18 kilograms are arranged unsecured in the luggage compartment. In the subsequent catapult test the entire body is suddenly accelerated to simulate the impact of a vehicle traveling at a speed of 50 km/h. The damage and effects caused by the unsecured test bodies are then examined and rated, the most important criteria being the extent of deformation of the backrest and the degree of retention of the test blocks.
TeMaKplus is an alliance of twelve partners from the business and research spheres. The aim is to establish magnesium as a lightweight material suitable for diverse uses in industrial production. Besides BMW, KWD and ThyssenKrupp MgF Magnesium Flachprodukte, TeMaKplus includes the university TU Bergakademie Freiberg and the Fraunhofer Institute for Machine Tools and Forming Technology in Chemnitz. Further research institutes and companies specializing in coating, forming and joining complete the alliance. TeMaKplus is funded by the Federal Ministry for Education and Research.