Aluminum wheel breakthrough

The patented technology from Fundo wheels of Norway is referred to as the hybrid manufacturing process and uses friction stir welding (FSW) as the key element to produce vehicle wheels. In 2007, the company won a US$50-million contract from Volvo to supply 600,000 aluminum wheels over three years made with the FSW process.

“We are extremely pleased to announce this supply agreement with one of the world’s leading luxury car companies, as it signals the confidence we have earned through the determined efforts of our employees to build quality products to meet the most exacting standards in the industry,” said Hroar Carlsen, CEO, Fundo Wheels.

Currently, Fundo’s hybrid FSW wheel technology is expanding into cutting-edge hybrid vehicles, SUV and performance vehicles, and lightweight focused platforms. Fundo’s FSW wheel designs vary in shape, color, branding and surface treatment depending on customer requirements. Wheels are manufactured in sizes ranging from 15” upward in diameter. The company says that demand for 19” diameter and larger wheels is growing for luxury cars, aftermarket treatments, sports utility vehicles and performance vehicles.

The company’s aluminum wheel products meet strict product quality and delivery requirements. Fundo obtained ISO 9001 quality certification in 1996, QS 9000 certification in 1998, VDA 6.1 in 2000, and ISO/TS 16949 in 2005. Fundo Wheels manufacturing facility is in Hoyanger, Norway. Here, along with the FSW process, the company’s manufacturing processes include alloying, low-pressure die-casting, heat-treating, machining and painting. “Fundo Wheels works in close collaboration with its customers in the design of new products, and has developed good relationships through its quality and service. Currently, Fundo Wheels is a main supplier of aluminum wheels to Audi and Volvo,” says the company.

Fundo Wheels has its own research, development and design organization using state-of-the-art technologies to develop wheels for today and tomorrows vehicle markets. Longer range product development using FSW includes examining and evaluating aluminum metal matrix composite centers welded to aluminum alloy rims. Additionally, Fundo is teaming with one of its shareholder partners – Timminco Ltd. – to assess, evaluate and develop magnesium wheels produced with the FSW technology.

Fundo Wheels is 47% owned by Timminco. Timminco Ltd. is primarily owned by AMG, a publicly traded company incorporated in the Netherlands. AMG is a global leader in the production of highly engineered specialty metal products and advanced vacuum furnace systems. Timminco is a leading producer of specialty and light metals. It produces silicon, magnesium, calcium and strontium alloys, magnesium extrusions, and fabricated products. These products are used in a broad range of industries including electronics, chemical, engineered extruded products, pharmaceutical, automotive and metallurgical. Timminco is a participant in the USAMP automotive vehicle development program.

Automotive Industries (AI) spoke to Hroar Carlsen, CEO, Fundo Wheels.

AI: Please tell us a little about your hybrid wheel technology – how is it different?

Carlsen: Our hybrid wheel technology can combine the advantages of casting with the advantages of wrought (or forged) processing. A wrought aluminum alloy is used for the rim where superior mechanical properties are of main importance. Whereas, casting can be used for the wheel disc, where design freedom is a premium consideration. In addition, a weight reduction cavity can be designed in the wheel disc periphery without use of cores or complex die technology. This can provide up to 25% reduction in weight, compared to die cast or spun cast wheels. The wheel disc can also be a forged design when weight reduction is paramount over design.

AI: For what kind of automobiles is this technology targeted?

Carlsen: Presently, the technology is targeted at wheels with rim diameters 19” and above and automobiles where reducing unsprung and rotating weight is of greater value. Since wheels represent static and rotating masses, wheel weight reduction has a bigger effect (about 30%) on fuel consumption and CO2 emission than static vehicle weight in general. Additionally, since wheels contribute to unsprung weight, reducing their mass improves vehicle road handling characteristics and passenger comfort.

AI: Tell us a little about your friction stir welding manufacturing process and the benefits of this process.

Carlsen: Very briefly, the friction stir welding (FSW) process is a solid state joining process with no melting of material. It is a plastic deformation process where the two materials to be welded are stirred together. This implies low heat input and no use of filler material, resulting in very good mechanical properties in the heat-affected zone. The FSW process was developed be TWI (The Welding Institute) in the UK in the early 90’s, and is now utilized in several industries including the aerospace industry. Fundo is the only wheel manufacturer presently using the technology to produce wheels, and has a worldwide patent on using the process for wheel manufacturing.

AI: Why is Fundo examining magnesium wheels and particulate reinforced aluminum metal matrix composite (Al-MMC) center sections for possible future wheel products?

Carlsen: The siren song of magnesium as the lightest weight structural alloy for automotive applications is certainly the main reason for this wheel product exploration. There is an obvious existing niche business in performance motor sports for such a product. Fundo has a ready-made partner for magnesium wheel development in Timminco, one of its owners. Timminco specializes in developing and producing magnesium alloy ingot and extrusions. The team plans to bring this product opportunity to the attention of the USAMP activity.

In the longer term, Timminco/Fundo is pursuing more robust magnesium alloy solutions that fit the requirements of future road-going lightweight and green vehicle wheels. In general, at the end of the day, reducing vehicle unsprung corner weight (both static and dynamic) is becoming a more and more valuable activity.

Particulate reinforcement of aluminum alloys adds significant fatigue value to the parent aluminum alloy without sacrificing parent alloy strength. In metallurgical terms, it creates a fatigue limit for the alloy that the parent alloy does not otherwise exhibit. Fatigue is a key performance characteristic that must be considered in the design of any wheel center.

Such Al-MMC materials can be cast using the same processes with which aluminum alloys are cast, and at increasingly competitive costs. As important, the Fundo FSW process technology may be able to intimately join such materials to aluminum alloy rims. Finally, if the joining metallurgy is demonstrated to be sufficiently robust, Fundo’s engineering CAD tools will be able to optimize center section designs using Al-MMC metallurgical advantages to further decrease wheel weight