The pipe is inserted into a recess at the joint, and there is no need to bevel the pipe ends or prepare the materials except to ensure they are clean. For butt welds, the fittings must be the same thickness as the pipes. Socket welding differs greatly from butt welding

Pipe flanges, fittings, and valves have different interface types: butt weld versus socket weld, for example. Welding can be divided into two types: socket welding and butt welding. Despite the fact that these two options appear to have their own pluses and minuses, you may be unsure which is best for your development project. 

What is socket weld?

A socket weld flange joins pipe fittings such as reducers, tees, and elbows with pipes. In socket weld joints, the pipe is permanently attached to the recessed region by a socket weld flange. In this way, socketweld pipe fittings are connected.

In corrosive fluid service, socket weld Flanges are problematic due to crevice corrosion. Corrosion is easily caused by the discontinuity in the smooth weld pipe fittings internals. Butt welding offers excellent strength, fatigue resistance, corrosion resistance, and temperature compliance.

Pros of SocketWeld

  • It does not require bevel ends
  • Easy to install and maintain
  • Low cost
  • Low welder skill required.

Cons of SocketWeld

  • Not suitable for pipes of large diameters
  • Leakage risk is present
  • Volumetric NDE examination not feasible
  • Low strength joint

What is Butt Weld

When butt welding, two pieces of metal are placed end-to-end without overlapping and  Socket welded together. Butt joints must have the surfaces of the workpieces to be joined on the same plane, and the weld metal must stay within those planes.

Differences Between Socket Welding vs Butt Welding

1. Diameters

Pipes with small diameters are usually welded with butt welding, whereas pipes with large diameters are welded with threaded welding or weld socket welding.

2. Ends

To fill the welding bead, the end should be bevelled from 30° to 37.5°. When socket welding, there is no need for a bevel, and the part can be directly welded.

3. Welding seams

What socket welding seams are fillet welding seams. Butt welding seams are butt welding seams, and the requirement for butt welding is high.

4. Non-destructive testing

Penetrant testing and magnetic particle testing are non-destructive methods for socket welding. Penetrant testing is used for stainless steel parts, and magnetic particle testing is used for carbon steel parts. A 100% ray inspection is conducted on the butt welding.

5. Design

A butt weld requires more skill and effort from a welder. By design, socket weld flanges are fillet welds. There are specific applications for butt weld flanges that differ from socket weld flanges.

6. Inspection Cost

Butt welds are usually inspected by surface and volumetric methods, again more expensive than socket welds.

7. Applications

Socketweld fittings are around half as strong as buttweld fittings. Usually, socket welding is used for small bore or NPS 2 piping.

8. Price

A socket weld fitting of similar size usually costs more than a butt weld fitting. The cost of welding installation is higher due to labour costs and the need for skilled socket welders.

9. Feature

Socket welds are easy to install. However, it takes approximately. At the bottom of the pipe is a 1/16″ gap to allow for thermal expansion. This gap can cause a stress issue that cracks the fillet weld of the fitting. In corrosive fluid service, socket welds are problematic due to crevice corrosion. As the pipe’s internals are discontinuous, it is easy for corrosion to occur.

Butt welds offer the best strength, fatigue resistance, corrosion resistance, and temperature compliance. Welding and fit-up are more difficult, requiring skilled Socket welders.

Pros of Butt Weld

  • Volumetric NDE examination is possible
  • High strength
  • Leakage risk is almost non-existent
  • Appropriate for higher thicknesses

Cons of Butt Weld

  • Not suitable for faying surfaces
  • It may require fixturing
  • High welder skill is necessary

Socket weld fittings are generally more expensive than butt weld fittings of the same size, but welding fittings are also more difficult to weld and fit-up properly, requiring more time and expertise.

To allow for thermal expansion, the socket weld coupling must have a gap of approximately 1/16″ left at the pipe bottom. The fillet weld of the fitting may overstress and crack as a consequence of this gap. In corrosive fluid service, socket welds may fail due to corrosion in crevices. The smooth pipe internals make corrosion easy.

Butt welds are superior in terms of strength, fatigue, corrosion resistance, and temperature compliance. Fit-up and welding properly require skilled welders and a long process.


As a result, socket welding Fittings are more expensive and have a higher pressure level than butt welding Fittings. When welding technology is required and the construction requirements are met, welding is an alternative. It is more convenient to detect socket weldingFittings if the pipeline medium does not require welding.

Socket Weld couplings have the disadvantage of an expansion gap between the OD of the pipe and the ID of the fitting. A crack between a pipe and a flange, fitting, or valve can lead to corrosion in stainless steel pipe systems. If complete penetration of the pipe is required, socket welds cannot be used, and butt welds should be used instead.

Pipe flanges, fittings, and valves have different types of interfacing: socket weld, butt weld, strung, etc. Two types of welding are well known: socket welding and butt welding. There are advantages and disadvantages to both, so you may wonder which would be best for your development endeavours. 

Socket Weld:

The ASME B16.11 standard describes socket weld fittings. A socket weld fitting embeds a pipe into a recessed region. It is simple to weld and assemble square cut pipes and fittings since they do not require angled ends or planning other than cleaning the outside. Socket weld fittings consist of two different lengths of pipe. The little pipe is inside the bigger one. The larger pipe is welded around its entire outside circuit. 

Butt Weld:

ASME B16.9 describes buttweld fittings. They are welded pipe fittings at their ends and have a similar thickness to channels. Butt weld fittings will have a slanted finish. Butt weld fittings are made by ramming two pieces of material into one another and welding them together. For good weld infiltration, the two pieces can be sloped in a few different ways. Both level stock and pipe or tubing can be butt welded. The weld is usually ground flush with the material surface. 


Weld sockets are easy to introduce. However, it takes approximately. A 1/16″ hole is drilled at the base of the pipe into the socket, allowing warm development to occur. Due to this hole, overpressure can cause the fillet weld to split. In destructive liquid administration, socket welds are inconvenient because they consume holes. The smooth pipe internals are irregular, making consumption easy. 

In terms of quality, weariness, erosion resistance, and temperature consistency, buttweld is the best. However, fitting-up and welding appropriately are progressively difficult, requiring a gifted  Socket welder. 


The quality of welding socket coupling is about half that of butt welding. Consequently, it is primarily used for a little pipeline with measurements of NPS 2 or smaller. 

In high-weight or high-temperature pipelines, buttweld maintains better quality. Therefore, it is used when a welded joint must have a quality equal to or higher than the base metal itself. 

Diameters & Ends:

For connecting funnels or pipe fittings with widths smaller than DN50 to channels with little distance between them, socket weld couplings are commonly used.

All shapes and sizes of channels can be welded by butt welding, and funnels with small widths can be welded by socket welded or strung welding.

To fill the welding dot, there should be an inclined end of 30 to 37.5°. Dividers that are very thick will have compound inclined ends. 

Socket welding fittings do not require an incline, and the part can be legitimately  Socket welded.


The cost of socket weld fittings is typically higher than that of butt weld fittings of comparable size. For the establishment, however, the additional costs of butt welding are higher considering the work cost and the gifted welder.

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