Many vehicle wheels that you see are made of cast aluminum due to the alloy in them being light and strong. Aluminum alloys used for wheels usually contain 97% aluminum. A second metal is added to provide durability since pure aluminum is too soft.
There three processes for making wheels from aluminum.
This is a process that shapes a solid piece of metal with force or compression. High-pressure machines will change the shape after the aluminum is heat treated. A wheel frame is forged multiple times to achieve the final shape. When the final shape is made, machining smooths and buffs the wheel.
This process is similar to the above except the aluminum is run between heavy stamps or wheels. The pressure from the rolling forces the raw material into the shape and thickness needed.
This process uses molten aluminum and mold. One from relies on gravity for the molten metal to fill the mold. Another form uses suction to force the melted to fill the mold. The metal cools and is removed from the mold. The desired shape is made from the one piece of metal. Computers monitor the process to check for pockets during the pouring and cooling stages. Gas pockets will make the frame weak.
Both methods of forging produce high-performance wheels that are commonly used for competitive racing. Most high-quality sports cars like Porsche and Lamborghini use forged aluminum wheels.
Wheel frames that are created as one solid piece are usually more expensive and very durable. Some wheel frames are comprised of separate parts that are welded or bolted together. Generally, there are three parts: an outer rim, inner barrel, and inside rim. The outer rim will have the decorative design. Regardless of the process, aluminum wheels are corrosion resistant, strong, and light.