Types of Flanges

Flanges are crucial components used in piping systems to connect pipes, valves, pumps, and other equipment. They come in various types, each designed for specific applications and operating conditions. Here are some common types of flanges:

Weld Neck Flanges (WN)

Welding neck flange
These flanges have a long tapered neck that is welded to the pipe. They are designed to transfer stress from the flange to the pipe, making them suitable for high-pressure and high-temperature applications.

Slip-On Flanges (SO):

Slip On Flange
Slip-On flanges have a slightly larger inner diameter than the pipe they are connected to. They are easy to install and are used in low-pressure and non-critical applications.

Socket Weld Flanges (SW):

Socket Weld Flange
These flanges are designed to be welded directly onto the pipe socket. They are used in smaller pipe sizes and high-pressure applications where welding is preferred over threading.


Threaded Flanges (TH):

Threaded Flange

Threaded flanges have internal threads that match the external threads of the pipe. They are used in low-pressure applications and where disassembly and reassembly of the connection may be required.

Blind Flanges (BL):

Blind Flange

Blind flanges are solid discs used to close the end of a pipe, valve, or vessel. They are commonly used for pressure testing, isolation, or to block off a pipeline temporarily.

Lap Joint Flanges (LJ):

Lap Joint Flange
Lap Joint flanges consist of two separate pieces—the stub end and the backing flange. The stub end is welded to the pipe, while the backing flange is free to rotate around the stub end. They are used in systems requiring frequent dismantling or alignment adjustments.

These are just some of the common types of flanges. Each type has specific advantages and is chosen based on factors such as pressure rating, temperature, pipe size, and the application’s requirements.