Wheel hubs, also known as rims, are barrel-shaped, centrally mounted parts on the axle that are used to support the tire's inner contour. Common automotive wheel hubs include steel wheels and aluminum alloy wheels. Steel wheels have high strength and are commonly used in large heavy-duty vehicles; however, steel wheels are heavy and have a single shape, which is not in line with today's low-carbon and fashionable concepts, and are gradually being replaced by aluminum alloy wheels.