Steel Pipe Flange

Pipeline flange, also called flange plate. A flange is a part that connects pipes in pipeline systems. Meanwhile, it is also applied for connecting between two devices (pipe with valves or with equipment).

The connection between two pipes can be directly welded together, but it is difficult to connect without welding. When the connection parts have problems, they will be hard to repair. The same problem also happened between the pipe and valve connections.

A flange is usually used for connecting pipes or valves, so it can solve the above problems easily.

How many parts are included in a flange connection?

The flange connection type usually comes with double units, with a gasket and some bolts & nuts to connect each other. (Firstly pipes are welded on the flanges, then valves and other equipment could be installed on the flanges).

When connecting these parts, put a gasket in the middle of two flanges, then tighten the flange screws, so the two will be connected tightly.

The flange connection way is convenient, flexible, and labor-saving.

In case of pipeline maintenance, we can remove screws on the flange, and take away corresponding pipes or valves. Meanwhile to replace new pipes and valves.

Flange connection has good strength and sealing, simple structure, and low cost. It can be repeatedly disassembled.

Failure mode

The flange connection mainly has a leakage problem, and the leakage quantity should be controlled within the allowable range of process and environment.

According to the connection way between the pipe and the flange, the flange can be divided into the following five basic types:

• Slip-on SO Flange.
• Weld Neck WN Flange.
• Socket Welding Flange.
• Thread Flange.
• Blind Flange.
• DN Flange.

Steel flange standards include European standards and American standards. Because of different dimensions, these two systems cannot interchange. American countries and China mainly adopt ASME or ANSI. Flange pressure rating in ASME could be divided into 150, 300, 600, 900, 900, 1500, and 2500 grades.

Common ASME standard for flanges:

ASME B16.5

Standards for pipe flanges and flanged fittings. (Covers sizes from NPS 1/2 through NPS 24 Metric/Inch including pressure-temperature ratings, materials, dimensions, tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings).

ASME B16.48

Standard for Line Blanks. (It covers all specifications for operating line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes).

ASME B16.47

Large Diameter Steel Flanges NPS 26 through NPS 60 (It covers all specifications for pipe flanges in sizes NPS 26 through NPS 60 and in rating Classes 75, 150, 300, 400, 600, and 900).

Pipeline Flanges are commonly used for carbon steel, alloy steel, and stainless steel.

Frequently used material as below:

• Carbon steel: STM A105.
• Alloy steel: ASTM A182 F11, F22, LF2.
• Stainless steel: 304/L, 316/316L.

Karisma Supply flanges in the below ranges:

• Range of Sizes: 1/2” to 40”, DN10 to DN3000 of steel flanges.
• Range of Thickness: SCH5 to SCH160 of steel flanges.
• Pressure range: Class 150, Class 300, Class 600, Class 900, Class 1500, Class 2500, from PN 0.6Mpa to PN 42Mpa.
• Type of Ends: Raised Face - RTJ - Flat Face.

• Carbon steel flange standards: ASTM A105, ASME A/SA 105, 350LF2.
• Stainless steel flanges standards: F304, 304L, 309S, 309H, 310S, 316, 316L, 317, 317L, 321, 321H, 347, and 904L.
• Alloy steel flange standards: ASTM A182, ASME A182, ASME SA182, ASTM A182 F1, F11, F12, F22, F5, F9, F91.
• ASME B16.5, ASME B16.47, ASME B16.48, AWWA C207, MSS SP-44.
• More standards are available in:
• DIN2573, DIN2577, DIN2630, DIN2631, DIN2632, DIN2533, DIN2634, DIN2635, DIN2636.
• BS4054, BS3293, EN1092-1, ISO 7005.
• JIS B2220.
• HG/T20592, HG/T21516-21518.