Alloy wheels are made from an alloy of magnesium and aluminium. Alloys are a mix of metal and other elements. They provide greater strength over pure metals, which is softer and more ductile.
Alloy wheels is not only more attractive than normal steel wheels, they are also a fraction of the weight and are far more durable. Therefore it requires less energy to rotate. This contributes to greater fuel efficiency as well as accelerating, handling and braking. Manufacturing begins with high grade aluminium alloy, containing 97 percent aluminium. A furnace heats up to 750 degrees and is liquefied within 25 minutes. The molten aluminium then flows directly into a mixer in which they inject argon gas, which enables them to remove the hydrogen. This increases the density making the aluminium less porous when solidified.
After adding powder titanium, magnesium and other metallic elements to further strengthen the aluminium, they blend in a chemical that draws aluminium oxide to the surface. The three wheel moulds are made of high strength of steel. The upper mould forms the inside face of the wheel, the forepart side forms the wheels edge and the lower mould forms the outer face that is the side of the design. The outer face is the most important mould as it forms the wheel’s design.
It takes about 3 to 4 weeks to produce a mould. Computer simulations check the flow and temperature of the liquid aluminium. These are factors that are critical to prevent casting defects. The casting machine is designed to fill the mould from the bottom via pressurised injection. Injecting upwards through the bottom rather than pouring downwards into the top reduces the risks of air bubbles which causes defects. The mould is then submerged into cold water to cool it off for better handling. The newly cast alloy wheels are trimmed and cleaned with a blade then put into a very hot oven for 12 hours.
The wheel is then tested and submerged into water to check for air bubbles. Thereafter the wheel proceeds to the painting area. First the base coat is applied then a coat of colour which can be anything from a classic silver or black to a flashy shade. Finally a clear paint is applied to prevent corrosion. There are random selections of wheels taken to test for performance and wear. The decorative cap that covers the centre hub is installed. It is this part of the wheel that typically bears the specific brand’s logo.
A1 Wheel and Tyre is a private family owned and operated company specialising in the warehouse and distribution of wheels and tyres to the automotive fitment trade. The company has a well established operation in Johannesburg, South Africa.