Flat steel flanges GOST 12820-80 Pn 6

Flat steel flanges PN 6, corresponding to the standard GOST 12820-80, are steel welded elements intended for connecting pipelines, pipeline valves and equipment. Flanges are used to create detachable connections, which simplifies the inspection, cleaning of the pipeline, and replacement of equipment.

Design of the flat flange is a detail of circular (sometimes rectangular) shape with evenly spaced holes along the outer edge. These holes are used for fastening studs or bolts, providing a reliable and tight connection. Flanges are used in pairs: they are put on the pipe and welded around the perimeter of the connection.

Designation in technical documentation

Flanges are designated as follows:
Example: “1-80-10 St.20”, where:

• “1” — number of product version;
• “80” — nominal bore (DN), mm;
• “10” — nominal pressure (PN), kgf/cm²;
• “St.20” — steel grade.

Areas of application

Flanges GOST 12820 are used in various systems:

1. Connection of pipeline fittings with pipelines.
2. Joining separate sections of pipelines to each other.
3. Connecting pipelines to equipment (e.g., tanks or devices).

Flange connections are in demand due to their ease of installation/dismantling, tightness, and high strength.