Automotive design expert Prof Mark White – honorary professor at Brunel University London, Industry Advisory Board Chairman for the Brunel Centre for Advanced Solidification Technology (BCAST) and Technical Director for Alumobility – outlines the top reasons why when it comes to aluminium, less is more. The article is republished with permission from Alumobility.
One of the most important reasons the use of aluminium is rapidly gaining traction in the automotive industry is because aluminium has one-third the density of steel, according to Alumobility’s recent white paper: When it Comes to Aluminium, Less is More. When comparing two identical vehicles with equal stiffness and load-carrying capacity – one made of aluminium, the other of steel – the aluminium vehicle body will be up to 45% lighter, which provides many advantages that will affect the future of the automotive industry.
1. Less weight = More efficiency
There are efficiency advantages of aluminium lightweighting in Battery Electric Vehicles (BEVs) as well as Internal Combustion Engine (ICE) vehicles. ICE vehicles manufactured from aluminium have better mileage, consume less fuel and produce less emissions. BEV’s do not run on fossil fuels but still require energy to move so the lighter weight of an Aluminium Intensive Vehicle (AIV) improves range capability. Because electric vehicle batteries can weigh as much as 2000 pounds, automakers are embracing the lightweighting benefits of aluminium as the market shifts to electrification.
2. Less weight = More secondary savings
A lighter aluminium body means a car can use smaller parts, including brakes, suspension parts, batteries, motors, yet achieve the same acceleration, performance and range with less emissions. In BEV’s, smaller batteries translate not only to greater range in traveling but also less extraction of raw materials and chemicals for manufacturing, which helps to protect the earth’s resources. The overall manufacturing of AIVs versus steel is more efficient in terms of materials and labor. This means that in addition to primary weight savings of, for example, 160 kg which is achieved by replacing 400 kg of steel with 240 kg of aluminium, the vehicle will also have another 40 to 60 kg savings in the weight of other materials savings.
3. Less weight = More safety
It is a common misconception that heavy cars are safer than light ones, but lighter weight AIVs are safer than those made of steel. Aluminium absorbs more energy that steel per Kg (lb.), so a lightweight aluminium vehicle can even be safer for the occupant than a comparable steel-based vehicle. When kinetic energy is absorbed in a controlled manner, vehicle occupants will be better protected from intrusion into the safety cell. In addition to being safer for vehicle occupants, an AIV is safer for everyone else–occupants of other vehicles, cyclists and pedestrians, as it carries less mass into any accident, therefore less energy to be absorbed.
4. Less weight = More durability
Since aluminium vehicles are lighter, they create less friction on key components such as tires and brakes. Less friction means that materials such as rubber and plastic emit fewer particle emissions and with less wear and tear, are expected to have a longer vehicle lifespan.
5. Less corrosion = More years in service
Automotive grades of aluminium alloys are less prone to corrosion due to the self-healing, protective barrier that forms in milliseconds when cracked, dented, or deformed. Unlike automotive steel grades, which are inherently susceptible to rust and rely on protective systems for durability, aluminium does not need a protective coating, even in severe environments.
6. Less weight = More payload and towing capacity
Pick-up trucks, SUVs and last mile delivery vehicles manufactured from aluminium can carry more cargo and/or have the potential for overall weight reduction compared to a steel reference vehicle. The lighter weight vehicles made of aluminium have a reduced impact on the roads, protecting an older infrastructure from extra wear and costly repairs. The lightweight aluminium body and chassis can enable secondary weights savings and result in lower cost per mile in running costs.
7. Less complexity = More efficiency in manufacturing
Compared to a steel-intensive vehicle, the process to manufacture an AIV requires fewer parts, translating to less complexity. AIVs require less of the following: tools, robots, joints, energy, factory emissions, less inventory, capital and sealers. These parts will be made from fewer alloys, allowing for simpler end-of-life recycling. More than 90% of a vehicle’s aluminium can be recovered and recycled–so an aluminium-intensive car at the end of its life can be recycled and practically made into another car body.
8. Less waste = More circularity
More sustainable than steel, aluminium is infinitely recyclable without a loss in its qualities, including lightness, durability and formability. Recycling aluminium scrap in a closed loop process allows vehicle manufacturers to reduce their carbon emissions immediately while end-of-life recycling offers an opportunity for future reductions. Steel is recyclable but it is important to know that it melts at 1400 degrees centigrade whereas aluminium melts at less than half that temperature, at 650 degrees. Since vehicles are manufactured with 600 kg or less of aluminium for every metric ton of steel, the energy savings of aluminium are noteworthy.
In conclusion, there are numerous benefits for accelerating aluminium use in motor vehicles. As outlined, infinitely recyclable, lightweight aluminium provides clearly defined advantages demonstrating its superiority as the material of the future for mobility.
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