The belt pulley is generally relatively large in size, and the manufacturing process is generally based on casting and forging. Generally, the larger size is designed by casting, and the material is generally cast iron. Generally, the smaller size can be designed for forging and the material is steel. Commonly used materials are gray cast iron HT200, HT250. The pulley should meet: light weight, uniform mass distribution, eliminate internal stress generated in the manufacturing, the pulley should be statically balanced.