Throughout the history of car manufacturing, a range of body materials have been used in the automotive industry. Steel has always been a material of choice as this metal offers strength and safety at a lower cost when compared to other materials. The automotive sector makes up for approximately 12% of global steel consumption, however, as the pressure on car manufacturers to be environmentally conscious grows, companies are looking to move away from using steel for body materials. Recent trends indicate that aluminium is quickly becoming the material of choice, replacing steel and other denser metals.
This article will explain the reason why aluminium is being used more and the differences between using aluminium and steel in car manufacturing.
As the effects of global warming and carbon emissions becoming increasingly more apparent, regulations are being developed to limit the damage the automotive industry has on the environment. The European Union aim to reduce the average vehicle emissions from 130g of CO2 per kilometre to 95g of CO2 per kilometre by the year 2021. One issue car manufacturers have battled with is the weight of automobiles, with reduced weights aiding adherence with the new regulations. Steel currently accounts for 60% of a vehicle’s weight, as aluminium is less dense than steel this will reduce the overall weight of the vehicle. Car manufacturers like Tesla and Ford have seen the benefits of switching to aluminium in a reduction in weight of the battery and payload capacity. However, as the strength of steel is four times the strength of aluminium, the thickness of aluminium must be increased to match the strength of steel.
One of the main concerns of car manufacturing is the safety of a vehicle, the use of aluminium helps to increase car safety as the metal has better energy consumption and a larger crush zone that folds more predictably on impact. Aluminium absorbs kinetic energy from crashes, this deflects the energy from transferring to the driver and the passengers of the vehicle. However, it is a combination of materials and design that help contribute to a vehicle’s overall safety. Aluminium use has been linked to overall car performance, boasting faster acceleration, shorter braking times and better handling.
There are some negatives to switching from steel to aluminium, one of which being the cost. Manufacturers typically spend two to three times more per kilogram for aluminium in comparison to steel. Using aluminium also changes the geometrics of the vehicle, aluminium requires a wider A-pillar, this can affect the overall driving experience and reduce the vehicle interior’s space efficiency. Major steel companies are trying to combat the complete switch to aluminium, developing steel alternatives like advanced high strength steel (AHSS). AHSS is considerably lighter in weight than normal steel, and offers minimum tensile strengths ranging from 500-800 MPa. Finally, steel is easier to recycle compared to aluminium and it is the most recycled material in the world.
It is clear that the automotive industry is still split between the use of aluminium and steel in car manufacturing. Some predict aluminium use will continue to increase, rising from 180kg per vehicle to 265kg per vehicle, eventually equating for 16% of the total vehicle weight. For every 10% reduction in weight, fuel economy improves by 7%, this results in improvements to the environment and money savings for the consumer. Although steel isn’t being completely replaced, it looks like manufacturers are choosing aluminium for parts such as vehicle doors, hoods and trunks as well as the vehicle body, bumpers and crash boxes.
Much of the aluminium used by the automotive industry is cast and, whilst mechanically strong, some parts are prone to porosity which makes the parts useless especially in fluid or air carrying applications. Sealing porosity in otherwise scrap cast parts has been the focus of Impregnation Services Ltd (based in Greater Manchester) for over 50 years and many manufacturers rely on them for final porosity sealing and quality enhancement in these parts.
Impregnation Services is based in Greater Manchester and offers vacuum impregnation and porosity sealing services to a range of industries. As market leaders in the industry, Impregnation Services offer both in-house and on-site services to suit the needs of clients.
With recent refurbishment to our facilities, our skilled team offer have experience working on castings from industries ranging from the automotive, energy and marine sectors. Our plant has the capacity to work on single parts to full production runs, offering services on 1000s of parts and specific applications. Our team strives to offer our customers the best in vacuum impregnation services.
If you would like to find out more about our porosity sealing services, contact a member of the Impregnation Services team on +44 (0)61 344 1004.