Human-powered lifting mechanism with hooks to 1.5 times the rated load as proof load test.
Power-driven lifting mechanism with a hook to two times the rated load as a proof load test.
After the test load hook lifted, there should be no obvious defects and deformation, the opening degree of the increase should not exceed 0.25% of the original size.
Inspection of the hook, the hook should be in low stress areas marking, including the nominal weight, factory standard or the trade name, inspection mark, production number and so on.
Hook discard criteria
Hook one of the following conditions should be scrapped:
① crack;
② dangerous section wear up to 10% of the original size;
③ opening degree increased by 15% compared with the original size;
④ hook body torsion超过10 °;
⑤ hook dangerous section or plastically deformed hook neck;
⑥ hook thread corrosion;
⑦ piece hook bushing wear up to 50% of the original size, replace the bushing;
⑧ piece mandrel wear hook up to 5% of the original size, you should replace the mandrel.
