Flanges  are metal or plastic parts that are used to connect pipes, fittings, equipment and other elements in pipeline systems. They allow you to reliably connect elements together, ensuring the tightness and strength of the connections.

Depending on the design features, flanges are divided into the following types:

1. Welding neck flanges (WN).
2. Socket weld flanges (SW).
3. Flat flanges (slip on or SO).
4. Threaded flanges (threaded or THRD).
5. Loose flanges (lap joint or LJ).
6. Blind flanges (blind or BL).

Flanges are regulated by the following standards:
1)  ASME B16.5 flanges  are high-temperature-resistant connecting elements. They are classified as heat-resistant and are used at temperatures above 80°C. 2) API  6 A
flanges   are flanges used in pipeline systems that operate under extreme loads. They were developed specifically for pipelines and equipment used in the refining of oil, explosive gases, water, steam and air at oil and gas industry enterprises.

3) Flanges  EN  1092-1  are pipeline steel flanges with working pressure from PN 2.5 to PN 400 and nominal dimensions from DN 10 to DN 4000.

4) ASME  B 16.47  Serie  A flanges   are large diameter flanges designed for connecting general industrial pipelines.

5) ASME B16.47 Series B flanges  – have a compact size, smaller drilling diameter and generally require fewer fasteners compared to Series A.

The following steels are used to manufacture flanges:

– Stainless steel:  A182 Gr. F304, A182 Gr. F304L, A182 Gr. F316L, A182 Gr. F316H, A182 Gr. F316Ti, A182 Gr. F321, A182 Gr. F321H, A182 Gr. F347, A182 Gr. F904L, A182 Gr. F9, A182 F11, X1CrNiMoCuN20-18-7, X2CrNi18-9, X2CrNiMo17-12-2, X2CrNiMoN17-11-2, X5CrNi18-10.

— Black  steel :  S235JR, S355J2, P235GH, 16Mo3 ,  A105 (SA105), A350 LF2 (SA350 LF2), A694 F42 (SA694 F42), A694 F52 (SA694 F52), A694 F60 (SA694 F60), A694 F65 (SA694 F65).
-Duplex : UNS S32205, SA182 F60, UNS S32750, SA182 F53, UNS S32760, UNS S31254, UNS NO8925, UNS NO8926.

-Nickel & Super Alloy:

Alloy 200 – UNS NO2200, Alloy 201 – UNS NO2201, Inconel 600 – UNS NO6600, Inconel 625 – UNS NO6625, Incoloy 800 – UNS NO8800, Incoloy 800H – UNS NO8810, Incoloy 825 – UNS NO8825, Monel 400 – UNS NO4400, Hastelloy C22 – UNS NO6022, Hastelloy C276 – UNS NO10276.