Main functions and material matters of crane pulleys

In cranes, the main function of pulleys is to thread and wind steel wire ropes. Pulleys are divided into movable and fixed pulleys based on whether the central axis is moving or not; According to the manufacturing method, it is divided into cast iron pulleys, cast steel pulleys, welded pulleys, nylon pulleys, and aluminum alloy pulleys. Cast iron pulleys, including gray cast iron (HT1533) pulleys and ball plug cast iron (QT4010) pulleys. Grey cast iron pulleys have good technological performance, have little wear on steel wire ropes, but are fragile, and are mostly used in light and intermediate operation levels; Ductile iron pulleys have higher strength and impact toughness than gray iron, so they can be used in heavy-duty operations.

Cast steel pulleys are generally made of ZG25 II and ZG35 II, with high strength and impact toughness, but slightly poor processability. Due to the hard surface, the wear on the steel wire rope is severe. It is commonly used in heavy and extremely heavy operating conditions. Welded pulleys are commonly used for large scale pulleys (D>800mm), and the material is A3 steel. This type of pulley is roughly the same as cast steel pulleys, but its weight is light, and some can be reduced to about 1/4. At present, nylon pulleys and aluminum alloy pulleys have been widely used in cranes. Nylon pulleys are lightweight and wear-resistant, but have low stiffness. Aluminum alloy pulleys have low hardness and minimal wear on steel wire ropes.