Flange selection is a systematic engineering decision-making process that requires careful consideration of operating parameters, standards and specifications, and material compatibility. Standardized procurement and selection processes can avoid assembly errors and safety hazards.

1. Define the basic parameters and confirm the nominal dimensions. Accurate data needs to be obtained from the design documents to match the diameter of the connected pipes or equipment. At the same time, the additional forces or bending moments caused by the pipeline's own weight, thermal expansion, earthquakes, etc. must be considered. These factors will complicate the flange design, and if necessary, the pipe load should be converted into equivalent pressure for selection.

2. Select a flange standard system. The standard system determines the flange size, pressure rating, and marking method. Select the appropriate rating (e.g., Class 75, 150, 300, 400, 600, or 900) based on actual temperature and pressure conditions. If the project involves the American standard system, then ASME B16.5 should be referred to.

3. Confirm the flange type. Select weld neck flanges for pipe connections and blind flanges for end sealing and isolation. The flange type mainly depends on the pressure rating, pipe size, and operating conditions. For specific selection, please refer to the Complete List and Selection Reference of Industrial Pipe Fittings.

4. Confirm the flange material. The flange material must be compatible with the pipe material, medium, and design temperature.

5. Confirm sealing and connection requirements. Determine the flange end face (RF/FF/RTJ), gasket type, and bolt configuration; verify the availability of the selected NPS, grade, and series of RTJ.

6. Select matching bolts and gaskets. Match materials to the medium, temperature, and corrosion conditions.

When selecting a flange, ensure that its strength rating matches the pipeline and strictly verify the rated values according to the design temperature and pressure.

Time：09/10/2026 16:13:24

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