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 hooks can be made of 20 high-quality carbon steel or forged with special materials such as DG20Mn and DG34CrMo. It is strictly prohibited to use cast hooks. The plate hook is generally made of A3 and C3 ordinary carbon steel or 16Mn low alloy steel. The longitudinal axis of the hook plate must be located in the rolling direction of the steel plate, and the hook plate is not allowed to be spliced. The hook piece of the plate hook shall be riveted with countersunk rivets, and the high stress bending part where the plate hook contacts the lifting point of the lifting object shall not be connected with rivets.