1. Purchase hooks should have technical documents such as the manufacturer's certificate and other technical documents; important departments should purchase hooks such as railways and ports, and the hooks must be strictly tested (inspection). 2. The hook shall not have any defects affecting the safe use performance; the hook defect shall not be welded; the surface of the hook shall be smooth, and there shall be no defects such as cracks, folding, sharp angle, burr, peeling, and over-burning. 3. It is possible to select two suitable positions at the shortest distance of the hook opening to print the mark that is not easy to wear, and measure the distance of the mark as the basis for detecting whether the opening degree changes during use. 4. The hook material can be made of 20 high-quality carbon steel or hook special materials such as DG20Mn and DG34CrMo. It is strictly forbidden to use casting hook. The material of the hook is generally applied to A3, C3 ordinary carbon steel, or 16Mn low alloy steel. 5. The technical conditions of the self-made hook should meet the requirements of GB 10051.1-88~GB 10051.5-88 (new standard: GB10051.1-2010~ GB 10051.5-2010) 6, the longitudinal axis of the hook plate of the board must be in the rolling direction of the steel plate, and the hook piece is not allowed to be spliced. 7. The hook plate of the board shall be riveted with a countersunk rivet, and the high-stress bending part where the hook of the board is in contact with the lifting point of the lifting object shall not be connected by rivets. 8. Fully enclosed welding is not allowed between the plate hook laminations, only intermittent welding is allowed. 9. Hooks that have been subjected to overload test shall be disposed of.