The demand for lighter vehicles will see automakers move away from using conventional steel over the next few years. Aluminium is considerably lighter than steel and is helping automakers meet tighter emission standards that are coming into force across the globe. At the same time, new high-tech steel products are being launched which may help in defending the share of steel in the market for lighter metals. Another option, carbon fibre, is also extremely lightweight, but scores low on price and manufacturability.
Aluminium use in light vehicles is expected to increase over the next decade as slashing the weight of bulky pick-up trucks and SUVs becomes a necessity in the US. Aluminium is more expensive than steel, but is around a third the weight of conventional steel. In the last two to three decades, the amount of aluminium being used in automobiles has tripled in North American and European cars. According to an estimate by the International Aluminium Institute, the transport industry accounts for some 25% of the total aluminium demand. Further, the passenger cars and light trucks sector uses two-thirds of this demand. Reducing fuel consumption and emissions are among the top priorities for the automotive industry. Automakers are increasingly focusing on these two areas not only to meet regulations but also to attract customers who are willing to pay more for fuel-efficient vehicles. According to Alcoa, a major aluminium supplier, about 83% of the potential car buyers were willing to pay more for fuel efficiency in 2012, significantly up from only 54% in 2008. So far, aluminium has generally been used in premium cars, but this is expected to expand to other less expensive models as well.
According to Aluminium Association, global automakers may use 249.5 kg of aluminium per car in 2025 compared with 148.3kg in 2009. The association predicts that in North America use of aluminium in cars will jump by 66% by 2025 to at least 3.7 million tons. In Europe, aluminium use in cars may rise to as much as 180kg per unit by 2020. Going by this trend, this month Norwegian aluminium firm Norsk Hydro ASA announced plans to nearly double production capacity of at its aluminium rolled product plant in Grevenbroich (Germany) to meet surging demand in the automotive industry. Aluminium supplier and technologist Novelis is focusing on providing engineered aluminium solutions to the automotive industry as well as producing new material concepts, like its fusion alloy to increase weldability and formability.
The trend has meant that steel manufacturers have had to develop new grades of high strength steel as they try to persuade automakers of its benefits over aluminium. On replacing steel with aluminium, Brandt, head of central technology and innovation management, thyssenkrupp says, “You need to use the right material, in the right place, at the right thickness, in the right shape and geometry to get the right weight. Steel is still a very competitive material compared to aluminium. Especially if you look at the wider scope and range of mechanical properties. The use of aluminium, plastics and composites will grow, of course, but it will not replace metals.” Studies reveal that the use of advanced high strength steel in North America almost doubled between 2005 and 2009 to 68 kg per vehicle. This is expected to increase further and is due to more than double to 166kg by 2025. There is still a preference for steel products over aluminium as they remain a cheaper solution. Cutting one pound of a vehicle’s weight with advanced high strength steel costs about 50 cents to an automaker while using aluminium costs four times as much.
Volkswagen recently started using thinner sheets of the higher strength steel, which is up to six times as strong as conventional steel. The new material helped reduce the weight of the latest Golf model by about 100kg. Ford opted for high strength steels, including an alloy using boron, for more than half of the Fiesta's body structure. Earlier this month, Nissan revealed plans to increase the use of advanced high tensile strength steel (AHSS) in new production models. The usage of AHSS is expected to increase by up to 25% of vehicle parts (measured by weight) in its new production models starting from 2017. This will help the company reduce vehicle weight by 15% with corresponding body structure rationalisation. Nissan, in collaboration with Nippon Steel, Sumitomo Metal Corporation and Kobe Steel, developed 1.2 gigapascal (GPa) ultra high tensile strength steel with high formability in October 2011. It will be used in the new Infiniti Q50 which will mark its entry in the North American market in 2013. The decision to use AHSS in its vehicles forms a large part of Nissan Green Program 2016, under which the company aims for a 35% improvement in fuel economy in all its models by the end of FY2016 compared with 2005.
Yet automakers are trying to make effective use of both metals. While aluminium has gained ground due to its light weight, high strength steel scores on the low cost benefit. Last month, Honda developed a new technology which combines aluminium and steel; the automaker is using the technology for making outer door panel of a car, which is conventionally made of steel. Combining the metals reduces door panel weight by about 17% compared with all-steel panels. This technology will be first used on the North American version of Honda’s new Acura RLX and subsequently on other car models.
Governments are also making investments in new research to cater to the tighter fuel efficiency standards which is scheduled to reach 54.5miles per gallon by 2025 in the U.S. and 75gm of CO2/km in Europe by 2025. Most recently, the US Department of Energy (DoE) last month granted USD6m to the United States Automotive Materials Partnership LLC (USAMP) and the Auto/Steel Partnership (A/SP) to develop modelling tools for deploying high-strength steels for lighter passenger vehicles. USAMP is a collaborative organisation of Chrysler, Ford and GM, which is jointly working with A/SP to develop and deploy a third-generation steel which can reduce weight of passenger vehicles.
Steel manufacturers have been making new investments to come out with lighter steel products, collaborating with OEMs. In February 2013, Tata Steel announced an investment of EUR2.3m (USD3.1m) in its plant in Ijmuiden, Holland, to develop ultra high strength automotive steel. The company has collaborated with numerous European automakers to better understand their requirements for upcoming models. Last year, Nippon Steel & Sumitomo Metal Corporation (NSSMC) announced plans to start manufacturing high-strength automotive steel sheets in Thailand, Mexico and Brazil. The company claims that it produces ultrahigh-strength steel sheets that are 60% stronger than the conventional high-strength steel sheet. This results in a vehicle weight reduction by about 10% to 20% as automakers would require less steel and still meet the safety standards.
New technologies such as electric vehicles (EVs) which have limited battery capacity (and hence range) have also necessitated creating lighter metal products. Last year, ArcelorMittal introduced a new range of ‘iCARe’ steel products specifically designed for use in the EV sector, helping automakers deliver lower CO2 emissions and improve fuel consumption for hybrid vehicles, at the same time extending range of pure EVs. ArcelorMittal has been aggressively researching advanced materials for automotive use. In 2011, the company spent USD306m in development of new steel products, solutions and processes to support low-carbon technologies in various industries. POSCO also developed a lighter steel to be used in EVs last year. The material, called POSCO Concept-Electric Vehicle (PBC-EV) is much lighter than the one in current usage. A car made of PBC-EV steel is expected to cut greenhouse gas emissions by almost 50% compared to regular cars.
These new developments underline the shift of steelmakers towards new steel products, as they face aluminum’s increased use in the auto industry and as automakers struggle to reduce emissions with tough targets looming. Also the fact remains that the aluminium industry does not have the production capacity to fulfill the demands of the market if every OEM was to use aluminium by 2015. As Brandt puts it, “There is the urgent need of co-operation between the steel and aluminium industry, between magnesium and aluminium industry... The big industries must co-operate.”
