Frequent and periodic safety inspections are an important part of hook safety.Safety inspections include pre-installation and in-service hook inspections.Dangerous section is the focus of safety inspection.
　　1、Check before installation and use
　　The hook should have the inspection certificate of the manufacturer (the rated lifting capacity of the hook and the inspection mark should be printed in the low stress area of the hook body), otherwise, the hook should be tested for the chemical composition of the material and the necessary mechanical property test (such as tensile force test, impact test).In addition, should also measure the original opening size of the hook.
　　2、Surface inspection
　　Through visual inspection, touch to check the surface condition of the hook.In the use of hook surface should be clean, no burrs, no sharp corners, there shall be no cracks, folding, over-burning and other defects, hook defects shall not be patch welding.
　　3、Internal defect inspection
　　Mainly through the flaw detection device to check the internal condition of the hook.Hooks shall not have internal cracks, white spots and any inclusions affecting the safety of use and other defects.If necessary, internal flaw inspection should be carried out.
　　4、Safety device
　　Condition should be installed to prevent accidental unhooking of the safety device.
　　The hook should be scrapped when one of the following conditions occurs:
　　1、Cracked;
　　2、Hazardous section wear up to 10% of the original size ;)
　　3、Opening degree increased by 15% from the original size;
　　4、Twisting deformation of the hook body exceeding 10°;
　　5. Plastic deformation of the dangerous section of the hook or the neck of the hook;
　　6. Corrosion of the hook threads;
　　(7) When the bushing of the tab hook is worn to 50% of its original size, the bushing shall be replaced;
　　(8) If the mandrel of the tab hook is worn to 5% of its original size, the mandrel shall be replaced.