According to the International Organization of Motor Vehicle Manufacturers, 97.3 million vehicles were produced in 2017, a 2.36% increase compared to 2016.
On average, 900 kg of steel is used per vehicle. The steel in a vehicle is distributed as follows:
- 34% is used in the body structure, panels, doors and trunk closures for high-strength and energy absorption in case of a crash
- 23% is in the drive train, consisting of cast iron for the engine block and machinable carbon steel for the wear resistant gears.
- 12% is in the suspension, using rolled high-strength steel strip.
- The remainder is found in the wheels, tyres, fuel tank, steering and breaking systems.
Advanced high-strength steels (AHSS) are now used for nearly every new vehicle design. AHSS make up as much as 60% of today’s vehicles body structures making lighter, optimised vehicle designs that enhance safety and improve fuel efficiency.
- New grades of Advanced High-Strength Steels enable carmakers to reduce vehicle weight by 25-39% compared to conventional steel. When applied to a typical five-passenger family car, the overall weight of the vehicle is reduced by 170 to 270 kg, which corresponds to a lifetime saving of 3 to 4.5 tonnes of greenhouse gases over the vehicle’s total life cycle. This saving in emissions represents more than the total amount of CO2 emitted during the production of all the steel in the vehicle.
- WorldAutoSteel, worldsteel’s automotive group, completed a three-year programme in 2013 that delivers fully engineered, steel intensive designs for electric vehicles. Known as the FutureSteelVehicle (FSV), the project features steel body structure designs that reduce the mass of the body-in-weight to 188 kg and reduce total life cycle greenhouse gas (GHG) emissions by almost 70%. The FSV study commenced in 2007 and concentrates on solutions for cars that will be produced in 2015-2020. Today we are seeing the material portfolio developed through the FSV programme progressively being introduced into new products.
The global transportation industry is a significant contributor to greenhouse gas emissions and accounts for about 24% of all man-made CO2 emissions (International Energy Agency, CO2 Emissions from Fuel Combustion Highlights, 2018 Edition, p 13). Regulators are addressing this challenge by setting progressive limits on automotive emissions, fuel economy standards or a combination of both. Many of the existing regulations began as metrics to reduce oil consumption and focused on extending the number of kilometres/litre (miles/gallon) a vehicle could travel. This approach has been extended into the regulations which now limit GHG emissions from vehicles.
Extending the fuel economy metric to meet objectives to reduce emissions is having unintended consequences. Low-density alternative materials are being used to reduce vehicle mass. These materials may achieve lighter overall vehicle weights, with corresponding reductions in fuel consumption and use phase emissions. However, the production of these low-density materials is typically more energy and GHG intensive, and emissions during vehicle production are likely to increase significantly. These materials are often not able to be recycled and need to be sent to landfill. Numerous life cycle assessment (LCA) studies show how this can lead to higher emissions over the entire life cycle of the vehicle as well as increased production costs.
A key factor in understanding the real environmental impact of a material is its LCA. An LCA of a product looks at resources, energy and emissions from the raw material extraction phase to its end-of-life phase, including use, recycling and disposal. worldsteel’s publication ‘Steel in the circular economy: A life cycle perspective’ explains how applying a life cycle approach is crucial to understanding the real environmental impact of a product.