閥門作為流體控制系統的核心部件，其質量直接影響管道系統的安全運行，合格檢驗需覆蓋外觀、性能、材質等多維度，通過科學檢測方法確保各項指標符合使用要求。

　　As the core component of fluid control systems, the quality of valves directly affects the safe operation of pipeline systems. Qualification inspection needs to cover multiple dimensions such as appearance, performance, and material, and ensure that all indicators meet the usage requirements through scientific testing methods.

　　外觀檢驗是合格判定的基礎環節。首先檢查閥體表面是否存在裂紋、縮孔、砂眼等鑄造缺陷，這些缺陷會導致介質泄漏或結構強度下降，可借助放大鏡（放大倍數不低于 10 倍）仔細觀察關鍵部位（如閥蓋與閥體的連接面、密封面）。其次核查尺寸精度，用卡尺測量法蘭厚度、螺栓孔間距等關鍵尺寸，誤差需控制在設計標準的 ±0.5 毫米范圍內，確保安裝時與管道匹配。此外，密封面的光潔度是重點，平面密封面需達到 Ra1.6μm 以上的粗糙度，錐形密封面的角度偏差不超過 ±1°，可通過標準樣板貼合檢查，透光間隙不得超過 0.03 毫米。

　　Appearance inspection is the fundamental step in determining qualification. Firstly, check the surface of the valve body for casting defects such as cracks, shrinkage cavities, sand holes, etc. These defects can cause medium leakage or a decrease in structural strength. Key parts (such as the connection surface and sealing surface between the valve cover and valve body) can be carefully observed with a magnifying glass (magnification not less than 10 times). Next, verify the dimensional accuracy by measuring key dimensions such as flange thickness and bolt hole spacing with calipers. The error should be controlled within ± 0.5 millimeters of the design standard to ensure compatibility with the pipeline during installation. In addition, the smoothness of the sealing surface is the key. The flat sealing surface should have a roughness of Ra1.6 μ m or more, and the angular deviation of the conical sealing surface should not exceed ± 1 °. It can be inspected by bonding with a standard template, and the light transmission gap should not exceed 0.03 millimeters.

　　壓力試驗是驗證密封性能的核心手段。強度試驗需將閥門內腔充滿水（或其他試驗介質），緩慢升壓至公稱壓力的 1.5 倍，保壓時間根據閥門規格確定（DN100 以下閥門保壓 10 分鐘，DN100 以上保壓 30 分鐘），期間不得出現滲漏或結構變形。密封試驗分殼體密封和填料密封兩項：殼體密封試驗壓力為公稱壓力的 1.1 倍，保壓 5 分鐘后檢查閥體與閥蓋的連接部位；填料密封試驗則在閥門全關狀態下施加公稱壓力，觀察閥桿處是否有介質滲漏，氣泡逸出量每分鐘不得超過 3 個（以氣體為試驗介質時）。對于高溫高壓閥門，還需進行高溫密封試驗，在設計溫度下保持壓力穩定，確保密封性能不受溫度影響。

　　Pressure testing is the core means of verifying sealing performance. The strength test requires filling the valve chamber with water (or other test medium), slowly increasing the pressure to 1.5 times the nominal pressure, and maintaining the pressure for a time determined by the valve specifications (10 minutes for valves below DN100 and 30 minutes for valves above DN100). During this period, there should be no leakage or structural deformation. The sealing test is divided into two parts: shell sealing and packing sealing. The pressure for the shell sealing test is 1.1 times the nominal pressure, and after holding for 5 minutes, the connection between the valve body and the valve cover is checked; The packing seal test applies nominal pressure when the valve is fully closed, and observes whether there is medium leakage at the valve stem. The amount of bubbles escaping per minute should not exceed 3 (when using gas as the test medium). For high-temperature and high-pressure valves, a high-temperature sealing test is also required to maintain pressure stability at the design temperature and ensure that the sealing performance is not affected by temperature.

　　材質檢驗需驗證材料成分與力學性能。通過光譜分析儀檢測閥體、閥瓣的材質成分，確保與設計要求一致（如不銹鋼閥門的鉻鎳含量需符合對應牌號標準），防止以次充好。力學性能測試包括硬度和拉伸試驗，截取閥體試樣進行硬度檢測（如鑄鐵閥門硬度需在 170-230HB 范圍內），拉伸試驗則需滿足規定的抗拉強度和伸長率指標，避免因材質強度不足導致使用中出現斷裂。對于用于腐蝕性介質的閥門，還需進行耐腐蝕試驗，將樣品浸泡在對應介質中（如 3% 氯化鈉溶液），24 小時后檢查表面腐蝕程度，失重率不得超過規定標準。

　　Material inspection requires verification of material composition and mechanical properties. By using a spectral analyzer to detect the material composition of the valve body and valve disc, it is ensured that they are consistent with the design requirements (such as the chromium and nickel content of stainless steel valves must comply with the corresponding brand standards), to prevent inferior products from being used as good ones. Mechanical performance testing includes hardness and tensile tests. The valve body sample is taken for hardness testing (such as cast iron valves, whose hardness needs to be within the range of 170-230HB). The tensile test must meet the specified tensile strength and elongation indicators to avoid fracture during use due to insufficient material strength. For valves used in corrosive media, a corrosion resistance test is also required. The sample should be soaked in the corresponding medium (such as 3% sodium chloride solution), and the surface corrosion degree should be checked after 24 hours. The weight loss rate should not exceed the specified standard.

　　操作性能檢驗關注啟閉靈活性與精度。手動閥門需測試啟閉扭矩，在全程啟閉過程中，扭矩應均勻變化，無卡阻現象，最大扭矩不得超過標準值（如 DN50 閘閥的啟閉扭矩不超過 30Nm）。電動或氣動閥門則需檢查驅動裝置的響應速度，從全開到全關的時間應符合設計要求，且在斷電或斷氣時能可靠處于安全位置（如自動關閉或保持原位）。對于調節型閥門，需通過流量測試裝置驗證流量特性曲線，實際曲線與理論曲線的偏差不得超過 ±5%，確保調節精度滿足系統控制需求。

　　Operational performance testing focuses on the flexibility and accuracy of opening and closing. Manual valves need to be tested for opening and closing torque. During the entire opening and closing process, the torque should vary uniformly without any jamming, and the maximum torque should not exceed the standard value (such as the opening and closing torque of DN50 gate valves not exceeding 30Nm). Electric or pneumatic valves need to check the response speed of the driving device. The time from fully open to fully closed should meet the design requirements, and they should be able to be reliably in a safe position (such as automatically closing or maintaining their original position) when power or gas is cut off. For regulating valves, the flow characteristic curve needs to be verified through a flow testing device. The deviation between the actual curve and the theoretical curve should not exceed ± 5% to ensure that the regulating accuracy meets the system control requirements.

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