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Socket Weld Fittings Types and Applications

We are already aware of the four connecting types for the pipe fittings: Slip on flanges, Threaded flanges, Socket Weld (counter bore), and Butt Weld Neck. In terms of the steel pipe fittings that you would use for your pipeline projects, you will find two of them to be quite popular: butt weld fittings and socket weld fittings.

Since both of them seem to have their share of advantages and disadvantages, you may be confused about which one is the best for your particular purpose.

To learn more about socket weld fittings, read on below.

Meaning of socket weld pipe fittings

A socket weld flange fitting is a pipe attachment detail with a socket and counter bore. In this case, you can insert the pipe into a recessed area of flange or fitting. To join the valves or pipes to the other sections of the pipe, seal welds of fillet type together. In several cases, socket weld fittings are a good choice. The benefits of high leakage integrity and great structural strength would be quite an essential factor that needs to be taken into consideration when designing your pipeline project.

Socket Weld Fittings Types and Applications

Usage of socket weld fittings

Socket weld fittings are termed to be used for low to medium pressure in confined spaces, and could easily be used in a diverse range of industrial processes.

Applied in the places where pipework has been deemed to be permanent. In addition, they have also been designed in a manner that provides characteristics of good flow.

Used in conjunction with ASME pipe and for to change to different dimensions.

Socket weld pipe fittings like reducers, tees, elbows, etc can be used at pipelines for conveying expensive, flammable, or toxic materials where there would be no scope of leakage.

Manufactured under ASTM standards and also according to ASME B16.5 /16.11

Types of Socket weld pipe fittings

Like the butt weld fittings, based on material types, socket weld fittings also include a variety of materials as stainless steel pipe fittings, alloy steel flanges, and carbon steel flanges. Based on the applications, it includes flanges, couplings, reducers, reducing tee, socket weld inserts, and socket weld elbows, etc.

Advantages and Disadvantages of Socket Weld

Below are some advantages and disadvantages of the socket weld:


The pipe often does not need to be end finished properly for the preparation of an insert weld.

Temporary tack welding usually doesn’t need alignment. It is because the principle in fitting would help to make sure that it has a proper alignment.

The socket weld insert will not be able to penetrate the bore of the pipe.

Costs of construction are sometimes lower than butt-welded joints. Due to the elimination of special machines, it lacks the exact fit-up bevel requirements.


The welder must make sure that the expansion gap between the pipe and the shoulder of the socket must be of a certain distance, often approaching 1.6mm.

The expansion gap and internal crevices in the socket weld system may promote corrosion with certain media. It would be because of this reason that they have been deemed to be less suitable for corrosive or radioactive applications.

These types of fittings would also be unacceptable for Ultra High Hydrostatic Pressure in food industries. The reason could be the addition to not allow full penetration. It would also leave gaps and crevices that would then become difficult to clean.

Differences between butt weld and socket weld fittings

In the case of socket weld fittings, the referred standard is ASME B16.11. You can insert a pipe in a recessed area of the fitting. You can square cut both the pipe and fitting and do not require any beveled end or preparation other than cleaning the outside. It will ease out the welding processes and installation.

When we talk about butt weld fittings, as pet standard ASME B16.9, the ends being welded onto the pipe end, the thickness would be the same as those of pipes. In this case, the end of the fittings could be beveled to match the application.

Application and installation of socket weld fittings

The socket weld usually has less strength resistance in comparison to butt weld fittings. So, SW fittings are used mainly for the smaller pipeline with diameters NPS 3 or less when available.

In the case of SW fittings, you can find it quite easy to install. Since it often requires around 1/6 inch of the gap at the bottom of the gap to allow the socket access, it also allows thermal expansion. However, the gap could lead to the problems of overstressing that will crack the fillet weld of the fitting. In addition, socket weld has also been found to be problematic in corrosive fluid service as a result of crevice corrosion. The media of the application must be considered.


Socket weld or SW fittings could help you in many ways, and in this blog, we have tried to cover almost all aspects that could help you get a better basic understanding. If you have any inquiries regarding  socket weld fittings and socket weld flanges, contact us today!

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