The hook shall be free of defects that may affect the safe use performance; The hook defects shall not be repaired by welding; The surface of the hook shall be smooth and free of cracks, folds, acute angles, burrs, peeling, burning and other defects. Two suitable positions can be selected at the shortest distance of the hook opening to print signs that are not easy to wear, and the distance of the signs can be measured as the basis for detecting whether the opening degree changes during use.

The hook is simple to manufacture and convenient to use, but its stress is not good, and it is mostly used in the working places where the lifting capacity is less than 80 tons; Double hooks with symmetrical force are often used for large lifting capacity. The laminated hook is riveted by several pieces of cut and formed steel plates. The whole hook will not be damaged in case of cracks in individual plates. It has good safety, but has a large deadweight. It is mostly used on cranes with large lifting capacity or for lifting molten steel drums. The hook is often impacted during operation and must be made of high-quality carbon steel with good toughness.