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What are Various Types of Flanges Used in Piping Applications?

The main use of flange is to connect pumps, pipes, valves, and other equipment to make a pipework system. Usually, flanges are threaded or welded, and you can connect two flanges by bolting them with gaskets and providing a seal that gives easy access to the piping system.

These flanges are available in many types like socket weld flanges, blind flanges, weld neck flanges, slip-on flanges, etc.

Here are various types of flanges used in piping systems that depend on other factors.

Types of flanges

Here are a few most important types of flanges available for piping applications:

Slip-on flanges

Slip on Flanges

The slip-on flange is a ring (with or without a hub) placed over the pipe’s end. The flange face extends from the end of the pipe by a sufficient distance to apply a welded bead to the inner diameter. As the name suggests, these flanges slip over a pipe and are known as slip-on flanges.

Weld neck flanges

Weld neck flange is also known as a high-neck flange or tapered hub flange. The weld neck flange has a neck that can properly transfer the pipe tension. It also helps to reduce the pressure gathered at the bottom of the flange. It is compatible with pipelines that operate at low or high temperatures and withstand high pressure.

Socket weld flanges

The socket weld flanges are connected on the outside just by a fillet weld. It is often not advisable for critical services. These are useful for the small-bore lines in your system. The static strength is equivalent to slip-on flanges, but the fatigue strength is 50 percent higher than double-welded slip-on flanges. Often used as an alternative to weld necks when space is a constraint.

Blind flanges

The production of blind flanges happens without a bore and is utilized to blank off the ends of pressure vessel openings, valves, and pipes. If you look from the point of view of bolt loading and internal pressure, the most overstressed flange types are blind flanges which are quite bigger.

Lap joint flanges

Lap joint flanges are useful with stub ends when the pipe is made of expensive material. E.g., a carbon steel flange can be added to the stainless steel pipe system as the flanges do not come into contact with the substance in the pipe.

Threaded flanges

A Note On Orifice Unions - ASMEANSI B16.36

Threaded flanges look identical to slip-on flanges, but the key difference is that the threaded flange is bored out to match the inside diameter of the particular pipe. The threaded flange is a type of flange that has taper pipe threads in its bore conforming to ASME B1.20.1 and is helpful in piping systems.

Materials useful to manufacture flanges

Pipe flanges can be manufactured from many different materials that depend on the piping material and requirements of the application. Selection depends on the factors such as economy, flow pressure, operating temperature, and environmental corrosion. Some of the most common materials include the following:

Carbon steel

It is steel alloyed usually with carbon. The high strength and hardness increase with carbon content, lower melting point, and ductility. This is the most common material grade.

Alloy steel

It is steel alloyed with one or more elements that change or enhance the properties of steel. Common alloys include chromium, molybdenum, nickel, vanadium, and manganese.

Stainless steel

It is steel alloyed with chromium in amounts above 10%. Chromium enables stainless steel to have a much higher corrosion resistance than carbon steel which rusts readily from air and moisture exposure.

Cast irons

Iron when it is alloyed with silicon, carbon, and several other alloys makes cast iron. Silicon forces carbon out of the iron and forms a black graphite layer on the exterior of the metal. Cast irons have good machinability, castability, and fluidity.


It is a low-density, ductile, and malleable metal with medium strength. It has better corrosion resistance compared to any other typical alloy and carbon steel. It is most useful during flange construction that requires low weight and strength.


It is an alloy of zinc and copper and often comes with additional elements such as tin or lead. It is characterized by good conductivity, cold ductility, high-temperature ductility, and good strength.


(Note we do not offer polymer grade materials but have written on them for your benefit below)

Polyvinyl chloride or PVC is a thermoplastic polymer that is easy to assemble, durable, and inexpensive. It is resistant to both biological and chemical corrosion. The addition of plasticizers makes it more flexible and soft.

Performance Features

Performance features are the flange properties that may be dependent on many other factors but are essential to consider. The properties include the following:


It is the toughness or strength of a pipe flange under pressure or stress. Durability is dependent on the flange compatibility and the flange design with the pipes and the material strength.

Easy of assembly

It is a qualitative measure of the efficiency of the disassembly and assembly process. For applications with flange used as a fix or temporary attachment, the ease of setting up and taking down is crucial.


It is the heaviness or mass of the flange. It is dependent on the material density and size. Industrial buyers must consider the strength of the pipe or pipe support while dealing with high or large-density flanges.


You can make out from the above different types of flanges, manufacturing, and performance features. You can choose the right steel flange manufactured from different materials like stainless steel, low alloy steel, carbon steel, duplex steel, or many more.

Choosing the right flange with the right material and knowing the elements that it faces during the application that uses the piping method is critical. We hope that this blog will help you identify the key things before purchasing flanges. To learn more about flange basics, visit

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