The flange face is designed per the ASME B16.6 for flanges up to 24 inches and ASME B16.47 for 26-inch flanges and larger. To prevent leakage problems, many kinds of flange faces are produced. For more info visit at:-https://www.texasflange.com/bl....og/meaning-and-types

Meaning and Types of Flange Faces
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Meaning and Types of Flange Faces

The ASME B16.5 code needs the flange face (flat face and raised face) to come with a specific roughness. It ensures that the surface is compatible with the gasket.

It helps provide a high-quality seal. A serrated finish, either spiral or concentric, is required, with 30 to 55 groves every inch.