Flange Sealing Surface Finish Requirements

1. Surface Smoothness: The sealing surface of the flange should be smooth to ensure a tight seal between the flange and the gasket. The surface roughness value (Ra) should be within the specified range, typically between 0.4 micrometers and 1.6 micrometers.

2. Surface Cleanliness: The sealing surface should be free of oil, dust, and other contaminants that could affect the sealing performance. Prior to assembly, the surface should be cleaned and prepared according to the manufacturer's guidelines.

3. Surface Flatness: The flange sealing surface should be reasonably flat to ensure proper alignment and seating of the gasket. Deviations from flatness should be within the specified tolerances.

4. Surface Imperfections: The sealing surface should be free of defects such as scratches, marks, or holes that could compromise the seal. Any identified defects should be repaired or replaced before assembly.

5. Gasket Compatibility: The sealing surface finish should be compatible with the type of gasket being used. This includes considering factors like gasket material, thickness, and design.

6. Corrosion Resistance: Depending on the application and environment, the sealing surface may require specific corrosion-resistant treatments or coatings to prevent rust and surface degradation.

7. Mateability: When joining flanges, the sealing surfaces should be mateable and aligned properly to ensure a tight seal. This includes considering factors like hub dimensions, face finishes, and gasket compression.

In summary, the flange sealing surface finish requirements involve achieving a smooth, clean, and flat surface that is compatible with the gasket and free from defects. By meeting these requirements, you can ensure a reliable and long-lasting seal in your piping system.