WHAT IS A FLANGE
Flanges are protruding ridges or rims that are commonly used to increase strength or distribute the load. Pipes, valves, pumps, and other pieces of piping elements are joined together with flanges to form a piping system. It also allows for simple cleaning, inspection, and modification. After welding, flanges are the second most commonly used joining method.
Despite the availability of a number of alternatives, Stainless Steel 304 Flanges remains the most versatile and commonly used stainless steel on the market. Grade 304 can be easily formed into a wide range of components for automotive, architectural, and transportation applications. This material is used to produce many varieties of flanges viz. Weld Neck, Blind, Spectacle, etc.
TYPES OF 304 FLANGES
Flanges aren’t a one-size-fits-all kind of thing. Aside from sizing, choosing the right flange design for your piping system and desired use will guarantee an efficient operation, a long life, and the best price. Flanges come in a variety of shapes and sizes, as shown below.
- Slip On – To provide adequate strength and prevent leakage, Slip on Flanges are slipped over the pipe and then welded both inside and outside. A raised or flat face can be found on these flanges. They’re best used in low-pressure environments. Slip-on flanges are also known as “Hubbed Flanges” and are easily identified by their slim and compact shape.
- Socket Weld – These flanges have a connection where the pipe is inserted into the flange and then the connection is secured with a single multi-pass fillet weld. Socket weld flanges have only one fillet weld on the outside and are often not recommended for critical services. Low-pressure pipes with small diameters require flanges of this type.
- Blind – Blind flanges are generally used to seal the end of the pipe or it’s opening, for this reason they have no bore. If work needs to be done inside the line, these flanges allow easy access to the pipe. Such flanges are often used to block an unneeded section of pipe or nozzle on a vessel.
- Weld Neck – This type of flanges require butt welding during installation. They are welded to the end of a pipe to create a flange that can withstand high temperatures and pressure. The weld neck flange has a ‘neck’ that can move the pipe tension, lowering the strain in the flange’s lower part.
- Threaded / Screwed – This design has a thread inside (female thread) the flange bore that connects to the pipe or fitting’s matching male thread. Although this flange is easy to use, it is not suitable for high pressure or temperature applications. The main advantage of the threaded flange is that it can be installed without the need for welding.
- Lap Joint – Lap joint flanges have a two-piece design that requires butt welding the stub end to the pipe or fitting and then using a backing flange to complete the flange connection. Their ability to hold pressure is very low hence, are used in low-pressure and non-critical applications.
- Spectacle – This flange resembles the shape of a spectacle (pair of glasses); two metal discs are connected together by a metal portion to form the flange. When a piece of equipment or a section of the line needs to be checked or removed from service Spectacle Blind flanges are used as a safety device to separate the equipment or line.
- Plate – These flanges are also known as flat flanges due to it’s shape as they have a flat even surface with a full face gasket that contacts the majority of the flange surface. Flat face flanges are frequently used in applications where the mating flange or flange fitting is cast.
- Reducing – Reducing flanges are a special type of flanges that are commonly used on projects that require the joining of pipes of various sizes. It is made up of a flange with a single diameter and a smaller diameter bore. The use of such flanges is avoided when there is an unpredictable change in the turbulence.
- Tongue & Groove – Matching grooves and raised sections can be found on these flanges. This gives them the advantage of being self-aligning and acting as an elastic buffer.