Chain Hoists enough material with high strength hook , and made of high alloy steel materials, the fracture does not occur in use, a higher safety factor. However, the use of hook should note the following points : 1 , chip hook does not allow splicing . 2 , hook surface and internal defects without affecting its usability . 3 , prohibiting the use of cast hook , so casting internal defects difficult to find and eliminate . 4 , prohibiting the use of manufactured or repaired weldment hook , so there may be cracks in steel welding .