"Wheels are an essential part of the train that is of most importance with related to the safety of the railway, bearing functions of guiding, moving and carrying trains. The safety and longevity of wheels are not only related to the wheel design, manufacturing processes, overhaul but also have a close relationship with the applying condition. Wheel design should both consider the usage requirements of trains and take full consideration of the relationship between wheel and rail, line conditions, bridges and many other factors. Wheel materials and production technology are steel smelting, casting, forging and rolling, heat treatment, machining. Penetrant detection and inspection determines the quality, longevity and safety of wheels.
Wheels vary in shapes, sizes, structures and materials. In terms of usages, three are three railway wheels: truck wheels, passenger car wheels, motorcycle wheels. In terms of structures, wheels can be divided into combination of wheels and integrated wheel. In terms of the production of radials, combined wheels can be divided into cast steel radials wheel center and rolled steel radials wheel center. In terms of production of solid wheel, it includes all-wheel forging wheels, rolling wheels, cast steel wheels, and forging-rolling wheels. Many countries developed silencer wheels, S-shaped spokes wheels, elastic wheels and so on to reduce the weight and noise of wheels.