Lightweight design for the premium segment

(Source: Audi Media Center)

Dynamic, safe and efficient: with the new A8, premium car manufacturer Audi has excelled itself in its core competence of lightweight design. For the car body, the so-called Audi Space Frame, GF Automotive provides eleven ultra-light aluminum and magnesium castings – more than ever before.

The new A8 fully lives up to the “Vorsprung durch Technik” slogan of the Ingolstadt-based premium manufacturer. The fourth generation of the luxury sedan impresses not only with the latest technology for highly automated driving but also with its innovative lightweight design. Already back in 1994, with the first generation of the Audi A8, the car manufacturer introduced a revolutionary body construction: the Audi Space Frame. The self-supporting aluminum structure weighed as less as 249 kilograms, making Audi one of the first car manufacturers in the premium segment to focus consistently on lightweight construction and aluminum components.

Unique mix of materials

For the latest generation of its top model, Audi has perfected the legendary Audi Space Frame, also thanks to the expertise of GF Automotive. For the first time an intelligent mix of four materials has been used to further reduce the weight and increase the torsional stiffness of the body structure. GF Automotive provides a total of eleven structural components for the Audi Space Frame: nine parts made of high-strength die-casting aluminum plus two magnesium components for the front and rear center console. GF Automotive is thereby making a decisive contribution to the intelligent lightweight construction concept of the new A8. Steel and carbon-fiber reinforced polymer (CFRP) complement the innovative material mix.

For the Audi Space Frame of the new A8 GF Automotive provides eleven ultra-light aluminum and magnesium castings – more than ever before

Thanks to the Audi Space Frame, the body of the A8 weighs around 40% less than a comparable steel structure

With its components, GF Automotive is making a decisive contribution to the intelligent lightweight construction concept of the new A8

High customer requirements

“The body of the new Audi A8 requires more large, supporting high-tech structural components casted in light metal than any other car model to date,” says Siegfried Wilhelm, Key Account Manager at GF Automotive. He has been looking after Audi for almost 20 years and understands the customer’s high requirements when it comes to technology and quality. GF Automotive ultimately secured the ambitious A8 contract thanks to its expertise in light metal and its know-how in casting large and complex components.

“With GF Automotive we have a strong partner to realize the challenging castings for the Audi Space Frame of the new A8.”

Marc Hummel Project Manager at Audi

Significant weight reduction

With the latest generation of its luxury sedan, Audi is setting new standards in the areas of driving dynamics, safety and efficient consumption. The use of very light, yet extremely stable, structural components is a major factor, as for example the increasing amount of electronics adds to the weight of the vehicle. Thanks to the Audi Space Frame, the body of the A8 weighs around 40% less than a comparable steel structure. The castings from GF Automotive replace a large number of sheet metal parts with a small number of lightweight structural components. The highly complex geometry of the largest aluminum parts which are connecting the side sills with the rear frame members, could not have been produced in steel. These parts made it possible to further expand the interior of the new A8. In addition, the A8 outperforms the previous model by offering up to 24% more torsional stiffness for precise handling and driving comfort. At the same time, the GF castings are used at crash-relevant points of the car body and increase the safety of the large sedan thanks to their high stability.

Innovative materials development

The innovative approach to materials and connection technology is essential for ensuring the high level of stiffness of the castings and the stability of the body structure. For the Audi Space Frame of its latest A8, Audi has developed new high-strength casting alloys. The development center of Audi and the R&D department of GF Automotive in Schaffhausen worked closely together in order to ensure optimum castability of the alloy and to make it ready at GF for serial production.

Greater value creation

A new, four-step heat treatment process is used to further increase the strength of the die-cast aluminum components. “This process enables us to manufacture stronger components even though the walls are up to 1.8 mm thinner compared to previous models”, states Siegfried Wilhelm. For the heat treatment as well as for the coating and processing of the castings, GF Automotive invested in new production lines at its location in Herzogenburg (Austria). Here, the 1.43-meter sill frame members are manufactured on GF Automotive’s largest high-pressure die-casting machines. The suspension holdings made of aluminum are also casted in Herzogenburg. The remaining aluminum and magnesium components are produced in Altenmarkt (Austria).

But GF Automotive is not only responsible for the casting, heat treatment, and coating of most Audi Space Frame components; the components are also mechanically processed at GF and partly pre-assembled before they are delivered ready for mounting to the Audi production plant in Neckarsulm (Germany). This is where the new A8 is produced for the global market. “In the scope of this ambitious assignment, we offer Audi even greater value creation and GF Automotive’s comprehensive expertise in lightweight design”, Siegfried Wilhelm says proudly.

f. l. t. r. Markus Beier (Project Manager, GF Automotive Herzogenburg), Georg Zerling (Project Manager, GF Automotive Herzogenburg), Christian Platzer (Project Manager, GF Automotive Altenmarkt), Siegfried Wilhelm (Key Account Management, GF Automotive), Marc Hummel (Project Manager, Audi Neckarsulm), Jan Gaugler (Development Casting, Audi Neckarsulm)