Audi A6 Lightweight Hybrid Steel-Aluminum Construction

http://www.eurocarnews.com -Audi AG - The bodies of the new Audi A6 and the A7 Sportback are also best-in-class. A hybrid steel-aluminum construction, they weigh roughly 15 percent less than a comparable all-steel body. They are made up of more than 20 percent aluminum, making them roughly 30 kilograms (66.14 lb) lighter than that of the previous A6 model.

The hybrid concept, in which the aluminum components are largely concentrated in the front end, improves the axle load distribution. Most importantly, though, it provides the basis for systematic lightweight construction. Depending on the version, the A6 weighs as much as 80 kilograms (176.37 lb) less than its predecessor. Audi has reversed the weight spiral yet again.

The crossbar in the engine compartment and the cross-members behind the front and rear bumpers are aluminum sections. The front strut domes are aluminum castings. The integral subframe behind the instrument panel, the rear shelf, the bulkhead to the trunk, the cross-member in the trunk, the front fenders, the doors, the hood and the trunk lid are made of aluminum panels. A new pretreatment process ensures that the steel and aluminum components can be painted in exactly the same way.

The passenger compartment of both the A6 and the A7 Sportback includes components made of hot-shaped steel. They can be found in the transition from the front section of the car to the passenger cell, in the A-pillars and the roof arch, as reinforcements for the center tunnel and the side sills, at the transition of the side sills to the rear section of the car, as cross-bracings in the floor panel and as B-pillars. In many zones, such as the bulkhead cross-connection, Audi uses tailored blanks. These are sheets of different thicknesses that have been rolled in some cases to different thicknesses.

In some areas, the steel components in the body already follow the ASF principle. The A6 and the A7 Sportback represent the gradual transition from the monocoque design to the new Multimaterial Space Frame