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New standards for aluminium


Audi is gradually stepping up its social responsibility. At the start of 2013, the Company signed up to the Aluminium Stewardship Initiative (ASI), which aims to develop a global standard for sustainable aluminum. As a pioneer of the use of this lightweight material, Audi is seizing the opportunity to influence the value chain – one of the goals of the Company’s corporate responsibility strategy.

The Aluminium Stewardship Initiative, which came into being in September 2012, aims to develop a pioneering sustainability standard governing the use of aluminum by the end of 2014. To that end it is drawing up ecological, ethical and social criteria. It is supported by the environmental organization IUCN (International Union for Conservation of Nature) based in Gland (Switzerland). It views its task as sensitizing society to nature and species conservation, and to the need for using resources sustainably and sparingly.

Set up as a non-profit initiative, the ASI is the first interest group in the world to focus on the creation of a sustainable standard for the use of the material aluminum. It is working in partnership with a large number of leading companies right along the value chain – stretching from the extraction of the raw material bauxite, through processing of the metal, to its recycling.
All companies that produce or use aluminum are called upon to sign up to the initiative.

 

Leading role in lightweight construction

Audi welcomes the moves to draw up a new standard because the initiative tallies with the Company’s wider stance. Within the automotive industry worldwide, the brand with the four rings leads the way in lightweight construction. As early as 1993, Audi presented the Audi Space Frame at the Frankfurt Motor Show, a gleaming silver show car with an unpainted body made from polished aluminum. The first Audi A8 went into production in 1994; its unitary aluminum body weighed a mere 249 kilograms (approx. 549 lb).

Since then, Audi has successively built on its lead; its lightweight construction principle has long been one of the Company’s mainstay technologies. To date, Audi has built around 750,000 cars with ASF (Audi Space Frame) body, far more than any other manufacturer. On each of these the body is around 40 percent lighter than an equivalent version made using steel. In the current model range, the A8 and R8 represent the ASF principle in its classic form; the TT features a special hybrid construction principle using predominantly aluminum, with some steel.

The ASF bodies are a matrix of cast nodes and extruded sections; aluminum panels form the surfaces and reinforce the structure. The technology results in a high standard of body rigidity that is the benchmark for precision, sportiness and comfort. The lightweight bodies have started to reverse the upward spiral in weight – they make it possible to reduce the size and weight of many automotive components, and in many cases mean a smaller engine can deliver the same performance. This reduces the loads at work in the event of a collision, and Audi’s engineers can design even lighter bodies.

At Audi, lightweight construction is far from a rigid fixation on a single material; rather it is about working intelligently and flexibly with diverse materials. The engineers at Ingolstadt and Neckarsulm always subject every material – steel, aluminum or fiber-reinforced polymer – to renewed testing tailored to the specific application, and analyze its potential and drawbacks. The motto is: “The right amount of the right material at the right place for optimal function.”

 

The next step

Audi is now in the process of taking the ASF principle a decisive step forward, in developing the Audi Space Frame using multi-material construction. By the year 2020, vehicle bodies will present an intelligent mix of different materials. The precise combination will vary according to vehicle category, but in future every new Audi is to be lighter than its predecessor.

The new construction principle is the right way to build cars on a volume scale. In terms of weight the new bodies are just as light or even lighter than bodies made exclusively from carbon-fiber-reinforced polymer (CFRP). They enjoy major advantages in other areas, too – not least the lower costs to the customer, and energy usage in a life cycle assessment.

Audi believes aluminum still offers abundant potential, especially in the shape of the new, higher-strength alloys. In parallel, the developers are working on further optimizing pressure die-casting methods. Heated tools will improve the material’s flow properties and make extremely thin walls feasible. Opened in 2013, the facility in Münchsmünster to the east of Ingolstadt has brought a key competence into the company in the form of an aluminum die-casting foundry.

All these developments are underpinned by the expertise that resides in the Audi Lightweight Design Center in Neckarsulm. Established in 1994, it is now home to some 180 specialists and spearheads the activities of the Company and indeed of the entire Volkswagen Group in the sphere of lightweight body construction. The lessons learned here have so far provided the basis for patents now running into the hundreds, for the honor of “European Inventor of the Year 2008” by the European Patent Office, and for four wins in the “Euro Car Body Award,” the world’s most important competition in car body design.

Audi’s lightweight construction is a holistic principle. From the very outset the Company made itself fully conversant with all the steps involved in aluminum technology, and brought the production process to maturity. Its portfolio of expertise now extends from development, through process engineering, to servicing and repair considerations.