What is a socket weld? What Are the different parts involved in one?

Last Updated on Apr 17, 2022

FYI, there are 4 kinds of pipe fitting connections: threaded, socket weld, flanged, and butt weld.

Socket weld fittings and butt weld fittings are both common types of steel pipe fittings that may be used in pipeline construction.

Although each has its advantages and disadvantages, you may be unsure which one is ideal for your needs. Because of this, we’ve taken on the task of putting together a comparison between the two. As a result, you’ll be able to tell the difference between a socket weld and a butt weld.

Keep on reading the full article to know what is a socket weld and what are the different parts involved in one.


What Is a Socket Weld?

A pipe may be attached to valves, fittings, or flanges through a recessed region using a Socket Weld. When it comes to pipe sizes, socket weld fittings are preferred over butt-weld fittings since they are more suited to smaller pipe diameters (Small Bore Piping).

Fillet-type seal welds are used to link pipe to Valves and fittings or to other sections of pipe. The advantages of high leakage integrity and exceptional structural strength make Socket Welded Joints construction an excellent option.

When compared to butt-welded structure, fillet welds and abrupt fitting geometry reduce fatigue resistance. However, this approach is still superior to most mechanical methods.

Let us help you understand the many components of a socket weld and how they are used.


Quick and Easy – Socket weld pipe fittings

For joining pipes, socket weld fittings are the way to go. The depression in the flange, valve, or fitting is used to insert a pipe. Fittings and pipes are joined using filter-type seal welds. Because of its high leakage integrity and structural strength, socket weld fittings are a suitable option for a broad variety of applications. The design of pipe networks must take them into account.

When seeking such fittings (or pressure rating), you’ll need to provide the OD measurements and the thickness schedule when seeking such fittings (or pressure rating).

SW (socket weld) is the abbreviation for socket weld pipe fittings. As a result, SW pipe fittings include items like SW couplings, SW tees, SW elbows, and others.


Socket weld fittings – What’s their purpose?

Because of their high-pressure ratings, these fittings may be used in a variety of industrial settings.

Low-leakage chemicals may be transported securely using SW pipe fittings like reducer, tee joints, and elbows. Using these fittings in a procedure where leaks might be hazardous is recommended. It is possible to use them as permanent connectors in pipe networks.

Excellent flow characteristics may be achieved with the use of SW pipe fittings. ASME and ASTM criteria and standards are often used in manufacturing these products. These standards and specifications cover tolerance, marks, pressure ratings, temperature ratings, dimensions, and materials. Other types of documentation, such as contracts, are also referred to.

  • Completely seamless pipes
  • Seamless tubes
  • Forged parts
  • Bars
  • Other components, including their mechanical and chemical qualities, are also mentioned.

Stainless steel, carbon steel, and alloy steel are all used to make socket weld pipe fittings, much as butt welds. In terms of materials, you may pick from a variety of SW flanges, coupling, and reducer options, as well as SW elbows and socket weld tees, depending on the kind of application.

Let’s take a closer look at the various kinds of socket weld fittings.


Different kinds of socket weld fittings.

Full-coupling.

This splice connects two pipes. Threads on both ends of a full coupling are used to join two pipes.

Coupling in half.

Half couplings are identical to full couplings, but the primary distinction here is that half couplings only have threads on one end, while full couplings have threads on both ends. This is the main difference. The half coupling’s unthreaded end is frequently welded or otherwise attached to the pipe.

Reducing coupling.

This fitting is used to join two pipes of various diameters together. If you have pipes of various sizes, you may use the reducing coupler to join them together.

Insert for socket weld reducer.

These are made in accordance with the relevant ASME and ASTM specifications. Pipes of various sizes may be connected at a lower cost with these pieces.

Union of socket welds.

This component is made up of three components that are all linked. The rotation of the two internal threads and the centerpiece closes the distance between the two ends. Because of this, socket weld unions must be tightened firmly in place before fusing the two ends of the union. As a consequence, there will be less seat warping.

Welding socket elbow.

Elbow sockets are available in 90 degrees and 45-degree configurations. The forging technique produces models with short and long radii. In pipe networks, this socket weld connection is critical. Fluids may be directed in a different direction by using it.

 Socket weld tee.

Using this connection, a branch may be linked at a 90-degree angle to two pipes going in the same direction. The principle of a socket weld reducing tee is quite similar. With a 90-degree connection, a smaller diameter pipe may be connected between two larger diameter pipes going in the same direction.

 Sockolet.

As with the threadolet and weldolet, the sockolet serves the same function. Using this technique, a smaller diameter pipe is welded to a bigger diameter pipe. The primary difference between the two is the inclusion of a socket in the sockolet that makes it easier to weld. The outlet contains this socket. This connection is capable of a 90-degree turn, and it has the ability to endure more strain.

 Crossing socket welds.

For branches linked to two pipes moving in the same direction, this connection allows for a 90-degree shift in direction.

Cap for socket weld.

The socket weld cap is used to seal the termination of a pipe, as the name indicates.

Flanges with socket welds.

At greater pressures, SW flanges are used on smaller diameter pipelines. The inner diameter of the flange features a recessed shoulder. This ensures that the pipe is attached to the fitting in a proper manner. Flanges and pipes are permanently joined by welding. Because of its outstanding flow properties, this kind of pipe connection is ideal.


Pros
  • To prepare the pipe for welding, it must be beveled.

  • Tack welds aren’t necessary to line pipes correctly most of the time. Proper alignment may be achieved thanks to the fittings’ design.

  • Threaded fittings may be replaced with socket weld pipe fittings since they have a reduced leakage risk.

  • Weld metal indeed gets into the pipe’s bore.

  • Socket weld fittings have cheaper installation costs than butt weld fittings. Compared to butt weld components, socket weld fittings have more flexible dimensions and do not need specific machining, making them more cost-effective.

Cons
  • In the food sector, socket weld pipe fittings don’t enable full penetration and contain fissures that are difficult to clean.

  • Socket weld pipe fittings need a certain expansion space between the socket and the pipe shoulder.

  • Corrosion is caused by socket weld fittings’ cracks and expansion gaps. To avoid issues with maintenance and operation, socket weld pipe fittings should not be used in applications that may include radioactive or corrosive chemicals.


Socket weld pipe fittings expansion

The 1/16-inch expansion gap may be achieved straightforwardly. This is when the socket weld contraction ring comes into play. This split ring has been designed to offer the smallest possible gap for socket welds. These have a good corrosion resistance since they are constructed of stainless steel. The ring may be quickly and simply fitted in the fitting to provide a secure connection. Even under tremendous pressure, it doesn’t vibrate.


It is common for socket weld bottoming clearances to decrease residual stress at the root of the weld and to provide for differential expansion of the mating parts. Hopefully, we were able to explain what is a socket weld and what are the different parts involved in one. With any luck, you now have a clearer grasp of the differences between socket weld and butt weld fittings.