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What Threaded Flanges Are and How Are They Used

A threaded flange is a device that connects a device that you can secure to a pipe length without the need for welding. With tapered thread, the threaded flange can be tightened onto the pipe without any leakage.

However, a seal weld is commonly used when it is appropriate. The nature of the threaded connection makes the threaded flange one of the viable options when welding is not feasible, like in explosives or highly flammable areas. The flange is commonly used only on small-diameter pipes.

threaded flange

In most refineries, manufacturing shipyards, and facilities, the highly explosive nature of the materials moved through the pipeline prohibits welding. A threaded flange is a good option in this environment when you assemble pipelines.

Using a tapered thread inside the flange, the pipe is tapered on the exterior and is threaded into the threaded flange. The flange joint becomes leak-proof and tight as the two tapers become enmeshed.

If the conditions exist that dem to be safe welding, a seal weld is occasionally placed around the junction of the flange and pipe.

Sometimes a seal weld is useful in talking about threaded connections. The special flange is usually used for the high-pressure piping system with smaller diameter applications. The larger the flange is, the harder the ability to machine a thread.


A threaded flange means the inner bore of the flange is a thread, the shape of the threaded flange is like the slip-on flange, so the threaded flange could be plate shape or with a hub for the longer threads.


The threaded pipe flange comes with a pipe connected to a pipe with an external thread on the end of the pipe. Thus, the flange thread should have the same thread specifications as the pipe thread.

The threaded flange advantage is that the piping system would be quite easy to assemble as there would not be any welding in the piping joint.


The threaded flange is usually supplied with a flat face (FF) or raised face (RF) sealing face. When a raised face is essential for the threaded pipe flanges, the standard height needs to be 1/16” for the face under class 400.

If the threaded pipe flanges are more or the same as class 400, the threaded pipe flange raised face needs the height to be 1/4”.

The threaded pipe flange is commonly useful in small sizes and during high-pressure situations. The threaded flange does not have welding in joints, so the flange could be usable in some situations. This way, it is not possible to arrange welding work.

Uses of Threaded flanges

They are beneficial when male NPT pipe connections are useful with high or explosive reactive media. These flanges are commonly used within the oilfield service.

Variety of threaded flanges

There are many available sizes of the flange variety and many pressure ratings. Though this is the case, they are useful most frequently for small piping systems. These piping systems are usually equal to or less than four inches.

Advantages of flanges

The key advantage of the flanges is that you can connect them to the pipes without the involvement of the welding process. It is an advantage and often a necessity. It is essential in the locations and industries that deal with explosive products.

Uses of flange

The common ways where you could use these flanges are:

  • Useful in highly explosive areas
  • Useful in applications where it is hazardous to do welding
  • Flanges are highly economical and help save time
  • Useful in the piping applications of small diameter
  • Can be fitted to various pipe sizes without the need for welding
  • Useful in situations where extreme pressure is present, and post-weld treatment is not an option.
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5 months ago

It’s interesting how the threaded flange’s leak-proof design relies on the enmeshing of tapered threads. This must ensure a secure and tight connection without the need for welding.

5 months ago

The threaded flange seems like a versatile solution, especially in environments where welding isn’t safe due to explosive materials in the pipeline. It’s great for assembling pipelines under such conditions. 

5 months ago

In what scenarios is a seal weld used alongside a threaded flange?

5 months ago

What advantages do threaded flanges offer over welded connections?