Aluminum and the Auto Industry

Aluminum has been used to manufacture automobiles for well over a hundred years. In fact the first sports car featuring an aluminum body was premiered at the Berlin International Motor Show in 1899. In 1901 Carl Benz, who went on to co-found Mercedes Benz, constructed the first aluminum car engine. Due to initial difficulties in metalworking with aluminum and its high price at the time, it took over 60 years for aluminum to become widely used in the auto industry. In 1961 Land Rover’s mass produced Buick 215 featured an eight cylinder V8 engine made from aluminum. The lightness of the engine was a revelation and it became an instant hit with race-car drivers. In 1997 Audi started production of aluminum body cars. The use of aluminum reduced the weight of the car bodies by up to 239 kg and paid great dividends in reducing fuel consumption.

Today, aluminum is the second most used material in the auto industry next to steel. It’s believed that 1 kg aluminum can replace up to 2 kg of steel or cast iron in the manufacturing process.

What is aluminum?

Aluminum is a metallic element. It’s classified with tin and lead in the “poor metal” category, as it’s extremely malleable. It’s been used by human civilization since ancient times. Aluminum oxides have been discovered in pottery artifacts from Ancient Egypt and Rome. At first, scientists believed aluminum to be rare and extraction was difficult. We now know that it’s the third most common element in the Earth’s crust, and the most common metallic element on Earth. Aluminum blends easily to make lightweight but strong alloys. Aluminum is very light, conducts heat and electricity very well and it’s non-magnetic. These properties make it ideal for a wide variety of uses, from construction to cooking utensils to auto manufacturing.

How is aluminum different from other metals?

Weight

Aluminum is light. Its density is one third that of steel.

Strength

Aluminum is strong. Aluminum alloys have tensile strengths ranging from 70 to 700 MPa. Unlike steel, aluminum does not become brittle at low temperatures. In fact the strength of aluminum increases when cold.

Flexibility

Aluminum’s strength is combined with flexibility, meaning that it can flex under load and bounce back from the force of impacts.

Malleability

Aluminum is extremely malleable, and can be extruded into any desired shape by passing it through a die. Aluminum can be extruded either hot or cold. It can be further manipulated through bending and forming operations.

Conductivity

Aluminum is an excellent conductor of heat and electricity. An aluminum conductor weighs around half the equivalent copper conductor with the same conductivity.

Reflectivity

Aluminum is a good reflector of both light and heat.

Corrosion resistance

Aluminum reacts with the oxygen in the air to form a microscopically thin layer of oxide. This layer is only 4 nanometres thick but provides excellent protection against corrosion. It even repairs itself if damaged.

Why does the auto industry need aluminum? How is it used?

The auto industry uses aluminum for the vehicle frame and body, electrical wiring, wheels, lamps, paint, transmission, air conditioner condenser and pipes, engine parts (pistons, radiator, cylinder head) and magnets (for speedometers, tachometers and air bags).

Using aluminum for automobile manufacture instead of steel gives a number of benefits:

Performance benefits

On average, aluminum is 10% to 40% lighter than steel, depending on the product. Vehicles made from aluminum have better acceleration, better braking and better handling. The rigidity of aluminum provides drivers with more immediate and precise control. The malleability of aluminum allows designers to engineer vehicle shapes optimized for maximum performance.

Safety benefits

Aluminum can absorb twice as much energy in a crash than the equivalent weight of steel. Aluminum can be used to increase the size and energy absorption capacity of a vehicle’s front and back crumple zones, enhancing safety without increasing weight. Vehicles made from lighter aluminum require shorter stopping distances, helping to prevent collisions.

Environmental benefits

Nearly 90 percent of automotive aluminum scrap is recovered and recycled. Recycling 1 ton of aluminum saves energy equivalent to 21 barrels of oil. Using aluminum auto manufacturing gives a 20 percent smaller lifecycle CO2 footprint compared to using steel. The Aluminum Association’s report The Element of Sustainability found that replacing a fleet of steel vehicles with aluminum vehicles can save 108 million barrels of crude oil and avoid 44 million tons of CO2 emissions.

Fuel efficiency

Vehicles with aluminum components can be 24 percent lighter than those with steel components. This saves 0.7 gallons of fuel per 100 miles, a saving of 15 percent in fuel consumption over steel vehicles. Similar fuel savings are made when aluminum is used in hybrids, diesels and electric vehicles.

Durability

Vehicles with aluminum components benefit from less need for rust repair and they enjoy an increased lifespan. Aluminum components are ideal for vehicles in challenging environments, including off-road and military.

What other metals are typically used in the construction / repair of vehicles?

Steel is still a mainstay of auto manufacture. It’s used in the body and frame, the fuel tank, engine block, axles, gears, brakes and cables. Copper is used in electrical wiring. Brass is used in bushings and the radiator. Other metals used to lesser amounts are: chromium, lead, magnesium, manganese, nickel and zinc.