The lifting hook for the manual driven lifting mechanism is tested with 1.5 times the rated load as the test load. The lifting hook for the power-driven lifting mechanism is tested with 2 times the rated load as the test load. After the check load is removed from the hook, there should be no obvious defects and deformation, and the increase in opening should not exceed 0.25% of the original size. If the hook passes the inspection, the mark should be printed in the low stress area of the hook, including rated lifting weight, factory label or factory name, inspection mark, production number and so on. The scrapped standard hook shall be scrapped in case of any of the following situations:

 

（1）crack;

 

（2）wear of dangerous section up to 10% of the original size;

 

（3）The opening is increased by 15% compared with the original size;

 

（4）the torsion deformation of the hook body exceeds 10°C;
 

（5）the dangerous section of the hook or the neck of the hook produces plastic deformation;

 

（6） hook thread is corroded;

 

When the wear of the hook bushing reaches 50% of the original size, the bushing should be replaced;

 

Today the hook spindle wear up to the original size of 5%, should be replaced the mandrel.