I. Appearance and logo inspection 

 Check the contents: whether the appearance of the valve is defective, such as cracks, bubbles, dents, etc.; check whether the logos, nameplates and surface treatment meet the requirements. 

 Standards: International standards include API 598, ASME B16.34, ISO 5208, etc.; China's standards include GB/T 12224 (general requirements for steel valves), GB/T 12237 (steel ball valves for petroleum, petrochemical and related industries), etc. 

 Detection method: Through visual inspection and feel inspection, determine whether there are obvious defects on the surface of the valve, and check whether the logo and nameplate information are correct. 

II. Dimensional measurement 

 Inspection content: Measure the key dimensions of the valve, including the connection port, valve body length, stem diameter, etc., to ensure that it meets the design drawings and standard requirements. 

 Standards: International standards include ASME B16.10, ASME B16.5, ISO 5752, etc.; China's standards include GB/T 12221 (valve structure length), GB/T 9112 (fange connection size), etc. 

 Detection method: Use calipers, micrometers and other measuring tools to measure the key dimensions of the valve to ensure that the design requirements are met. 

III. Sealing performance test 

 Static pressure test: Apply hydrostatic pressure or static pressure to the valve to check the leakage after maintaining it for a certain period of time. 

 Low-pressure airtightness test: When the valve is closed, apply low-pressure gas to the valve and check the leakage. 

 Shell strength test: Apply hydrostatic pressure above the working pressure to the valve to test its shell strength and pressure resistance. 

 Stem Strength Test: Assess whether the torque or tensile force on the stem during operation is within the safe range. 

IV. Operational performance test 

 Opening and closing torque and speed test: Test the opening and closing torque, opening and closing speed and operation feel of the valve to ensure smooth operation and within a reasonable torque range. 

 Flow characteristic test: Test the flow characteristics of the valve at different openings to evaluate its ability to regulate the fluid. 

V. Corrosion resistance test 

 Evaluation content: Evaluate the corrosion resistance of valve materials to working media. 

 Standards: International standards include ISO 9227 (salt spray test), ASTM G85, etc. 

 Detection method: Place the valve in the salt spray test chamber to simulate the corrosion environment and test the durability of the material under corrosion conditions. 

 VI. Durability and reliability testing 

 Repeated opening and closing cycle test: The valve is repeatedly opened and closed to evaluate its durability and reliability in long-term use. 

 Temperature stability test: Test the performance stability of the valve under different temperature conditions to ensure that it works normally in extreme temperature environments. 

 Vibration and impact test: Place the valve on the vibrating table or impact table, simulate the vibration and impact in the working environment, and test the stability and reliability of the valve. 

VII. Leak detection 

 Internal leak detection: Test the internal sealing performance of the valve under closed state. 

 External leak detection: Check the external seal of the valve in use to ensure that there is no media leakage. 

VIII. Other tests 

 Safety valve test: For the safety valve, tests such as fixed pressure and back seat pressure are also required to ensure that it complies with the specifications and relevant procedures.