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1. Poor design, such as an insufficient safety factor, unreasonable structure, and excessive concentration of internal stresses. The design shall comply with **standards and relevant specifications; the structure shall be rational to avoid excessive concentration of internal stresses. New products can be produced in bulk only after passing field testing. 2. The forging and casting quality is poor, with defects such as folds, cold shuts, pores and slag inclusions, loose structure, hidden cracks, as well as uneven wear, inconsistent material quality, and material that does not meet the design requirements. Strictly adhere to operating procedures and process discipline, and forge, cast, and process in accordance with drawings and technical requirements ； A comprehensive quality assurance system should be established; important valves shall undergo material analysis and flaw detection, and strength tests shall be carried out before leaving the factory. The persons responsible for these tests and assembly processes should be identified to indicate their accountability. 3. Poor welding. Cracks caused by welding defects, excessively brittle welds, excessive internal stress, and other reasons. Welding must be carried out strictly in accordance with the operating procedures; thorough inspection and flaw detection are required after welding. Strength tests should be conducted before the product leaves the factory, and the person responsible for conducting these tests should be identified. 4. Improper installation, skewed and twisted. It should be installed in the center to ensure even stress distribution, and to prevent issues such as misalignment or gaps in the flange; large valves should be fitted with supports ； Cast iron valves and non-metallic valves are brittle, so special attention should be paid and measures taken. 5. Improper selection. The valve cracked due to operating conditions that were not suitable for it. Valves should be selected strictly in accordance with the operating conditions (medium, temperature, pressure). When selecting valves for critical locations or under harsh operating conditions, sufficient margin should be allowed to prevent the use of cast iron valves in place of steel valves. Strength tests should be conducted on the valves prior to use. 6. The pressure and temperature inside the valve are too high, with large fluctuations. The safety systems of the installations and equipment need to be sensitive, pressure and temperature readings must be accurate, operations should be smooth, and emergency measures effective. 7. Valves damaged by water hammer. Smooth operation is required, along with devices and measures to prevent water hammer, as well as protection against sudden pump shutdowns and rapid valve closure. 8. Freeze cracking. Valves should be equipped with insulation or heating facilities; valves that are not in use during cold weather should have any water present in them removed, especially cast iron valves and non-metallic valves. 9. Accidental collision. The stacking of heavy objects is not allowed; during construction, care must be taken to prevent objects from hitting the valves. The covers over the pits should also be used to prevent them from damaging the valves, especially cast iron and non-metallic valves. It is also necessary to prevent the valve from bursting due to excessive operating force. 10. Valves that have suffered fatigue damage beyond their service life or exhibit early fatigue defects should be replaced. Vibration prevention facilities and measures should be in place, and the operation must be smooth.