Load test shall be carried out for new hook, and the measured opening of hook mouth shall not exceed 0.25% of the original opening. During use, the hooks shall be frequently checked for cracks, serious deformation, corrosion and wear. The hook shall be tested once a year. During the test, the static test shall be carried out with 1.25 times of the allowable working load for 10min. The magnifier or other methods shall be used to check that there shall be no cracks, cracks and residual deformation.

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.