What is a Socket Weld?

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We use different types of welding for connecting two metal sheets or components. Socket weld is a type of welding that helps connect the elbows, tees, reducers, or other sort of fittings to a pipe. This method is suitable only for flowing fittings having a small diameter.

In a socket weld, the welder permanently joins the fittings to a pipe. The fittings connected in such a way are known as socket weld fittings. Socket weld is famous for its extra sturdiness and leakage capacity. Due to its structural integrity, it has several applications in different fields.

So, what is a socket weld? Socket Weld is a method of welding that works by inserting the pipe into a flange. The welder inserts the fittings like elbow, tees, or other reducers into the recessed area of flanges and then welds them together. Two layers of welds are good for making a sturdy weld.

Socket Weld Symbol

Socket Weld Symbol

Image Credit: www.wermac.org

To weld a socket, you need to insert the fitting into the secluded region of the valve, pipe, or flange. After inserting the fittings, you can weld both the fitting and the pipelines together. By welding in such a way, the integrity of the weld increases many times. This diagram illustrates a typical socket weld system. All the points or components have proper labeling. In this process, the welder inserts the pipe into the recessed portion of the flange in SW welding. The socket weld fitting material must have an integrated composition. Due to this reason, the Socket welds have durability. The welder places the fillet welds at an angle of 90 degrees shown in the diagram. These inclinations add to the sturdiness of the weld. The elbows labeled in the diagram helps in turning or directing the pipes within the industries.

Expansion gaps are available in the fitting that helps expand the pipe in the summer season. In summer, the components made of metallic parts dilate in length and size due to elevation in temperature.

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Socket Weld Pipe Fittings

Socket Weld Fittings belongs to a class of durable fittings. These SW fittings are useable for making a connection between two passages.. You can use this fitting to bypass a flow or to recover any leaking pipe. The socket weld fittings done at an angle provides great integrity and sturdiness to the weld.

When Would You Use Socket Weld Fittings?

Socket words are easily applicable and installable. But in certain conditions, the applicability of the Socket welds is manifold. Following are the primary uses of socket weld pipe fittings:

a. For a Flow of Toxic Materials:

Socket welding helps in building an infrastructure of pipes where one uses toxic or poisoning materials. The corroding acids or flammable liquids can deteriorate the pipes welded by other mechanisms. But socket Weld Fittings have a greater rate of durability. That is why these welding have applications in places where toxic, corrosive, flammable, and expensive materials pass. In industries, you cannot compromise on any leakage or hole. Because here expensive and corrosive chemicals have usage. So, socket welding assists industrialists in preventing such issues.

b. Usability With ASME:

Socket Weld Fittings have applicability in connection with the ASME pipes. These fittings are available in different sizes and work well with welding pipes having the same diameter or pore size.

c. To Achieve a Smooth Flow:

You can use this type of weld fittings in places where you want to avoid any turbulent flow. Socket Weld Fittings are the ultimate solution for your industries, where you need a smooth and flawless flow. Peoples specifically use these weld fittings in areas where liquids or solvents flow permanently. In such places, sturdy and durable pipework is demandable. So, good flow characteristics are achievable by using these welds.

d. Compatibility With ASME Version:

Industries produce socket weld fitting by the ASTM standards. Moreover, these fittings have a great deal of compatibility with the ASME B16.11. Following parameters are present in top-notch B16.11 standards:

  • Ratings related to bearable pressure and temperature
  • Dimensions of fittings
  • Pressure and heat tolerances,
  • Diameter marking,
  • and materials needed for carbon and steel alloys

Suitable materials for these Socket Weld Fittings are forgings of steel and carbon, bars, flawless pipe, and coherent tubes. All these materials are compatible and have a similar conformation to the fittings.

These materials satisfy the requirements of chemicals, melting or decomposition points, and mechanical attributes demands like sturdiness, pressure bearing capacity of different models of ASTM. Socket Weld Fittings are available in three different pressure-bearing capacities. These include Class 3000, class 6000, and class 9000.

Fittings for Socket Welding Pipe Systems

Fittings For Socket Welding Pipe Systems

Following are different types of fittings for SW welding:

01. Full-Coupling:

A full coupling is beneficial for joining two pipes. It usually joins the main pipe to an additional branch pipe or a valve.


02. Half-Coupling:

This type of fittings helps in making a running connection of the pipes. It helps to run a compartment when there is a leakage in the outer fitting. The half coupling also helps in making a branch connection.


03. Reducing Coupling:

In some situations, the pipes to be weld have different sizes or diameters. To weld such pipes of various sizes, reducing coupling is applicable. These fitting have an inner, narrow hole and an outer wider hole. These two holes fit in the pipes of their respective sizes.

Reducing Coupling

04. Reducer Insert:

Socket Reducer Inserts are compatible with any model of SP-79. These reducers help in establishing a quick and economic junction of pipes. Moreover, the socket weld made in this way has a standard size and quality.

Reducer Insert

05. Union (MSS Sp-83):

This pipe fitting has a design of screw joint. It has three interconnected pieces in it. The two among them are outer pieces and one inner piece. The inner section helps in the threading and tightening of the fittings. The welder must tight or screw up the joints or junctions before welding the union. It prevents future warping and tears.

Union (MSS Sp-83)

06. Elbow 90°:

In the infrastructure of Industries, where thousands of pipelines are present. You may need to change the direction of pipes at certain positions. These elbows having a 90-degree inclination angle are useable in such places. These elbows help in directing the pipes or changing the flow line of the pipeline.

Elbow 90

07. Elbow 45°:

 Sometimes, a minor tilt is enough for making a pipeline connection. So, the elbows with an angle of 45 degrees are helpful in such circumstances.

Elbow 45

08. Tee Straight

These Fittings are specifically helpful in extending a branch from the mainstream of pipe. The name Tee represents that two stems can stem out of a single primary passage.

Tee Straight

09. Cross

It helps in making a connection between four pipes. The junction of all the pipes is at ninety degrees to the other. Moreover, you can also use it to stem out three sprigs of the tubes from the mainstream passage.


10. Cap (End Cap): 

These Fittings help cap or cover the end of a pipe. They assist in blocking the flow of liquid or the end of a connecting channel.

Cap (End Cap)

11. Socket Weld Flanges:

Socket-weld flanges have applicability in areas of smaller sizes where liquid has high pressure.

These flanges have a hole or sunken area inside. The welder inserts the pipe into the secluded end or socket end. In the next step, he welds the edges by applying fillet weld around. In this way, a smooth bore forms. It guarantees the streamline and better flow of the liquid or gas inside of the fitting pipe.

The range of specifications for Slip-on Pipe flanges having a connection hub starts from ½” to 24”. Socket Weld flanges and valves are available in all types of material Composites, diameters, and sizes.

There are different types of Socket Weld pipe flanges available in the market. Various types of interfaces are available such as:

  • raised face
  • Flat face,
  • or RTJ facing.

However, these different faces have their specifications or recommendations. For example, if you want to use a raised interface for socket weld pipe flange, 1/16” is the recommendable height for SW pipe having grading less than 400 no.

If you want to take the pipe flanges of 400 and more, most suitable or recommendable height for the standard flange with a raised interface is not more than ¼”.

S W flanges are available in the market with a composition of different materials, like carbon socket, mild steel pipes, and stainless steel S W pipe.

Socket Weld Vs. Butt-Weld

The socket weld usually has around half of the less load-bearing capacity than the strength of butt weld fittings. Due to less sturdiness and integrity, the SW fittings are mainly applicable at places having small pipelines. These fittings are workable with a diameter of NPS 2 or even narrower than this.

On the other hand, butt weld fittings help in establishing a sturdy and better strength. Another perk of butt weld is that it has greater heat-bearing capacity. That is why it is better to use butt welds in places having high temperatures or high-pressure pipelines.

Another factor that helps in making a good decision is the price or cost factor. You must be conscious of the cost-efficiency of a process before selecting it. In the comparison of butt weld vs socket weld, the decision becomes a little bit difficult. Because in socket weld, the cost of components, materials, and welding is greater than the butt welding. The expenditures are much more than a butt weld of the same size in the socket weld. Hence, you can prefer to choose butt weld. But the installation cost of a butt weld is manifolds greater than a socket weld. So, a butt Weld cuts the prices in terms of components but has extra expenditures of installation.

The preferred standard for socket welding is ASME B16.11. In a socket weld, you can insert the pipe into the fitting with a recessed area. Every fitting must have a deep part. There is no need for any preparation in the socket welding. You only need to clean the surfaces and cut the pipe, and fitting in a square shape. The ends are in a beveled form. So, a socket weld usually has a low installation cost and is easily performable.

Contrary to it, the referred standard for butt weld is ASME B16.9. In this process, the ends of the pipes and the fittings must have a compatible size or dimension. The thickness of both the pipes and fittings must be the same. So, it has an extra installation cost, and the ends of connecting tubes, in this case, can be beveled.


The closing Terms are that you must choose a socket weld in situations where the size of the pipe is not very wide. There is no need for any extra installation cost in such cases. You can make a socket weld by simply inserting the fitting pipe into the required size fitting and weld it. The socket weld fitting material must be of superior quality.


How to Install – Socket Weld Vs. Butt Weld?

In a socket weld, we insert the pipe into the hole of the valve or other pipeline. In the next step, we weld them together. Contrary to it, in butt weld, you need to join the two ends of the pipes and weld them at the same level. A butt weld has beveled ends.

Is A Socket Weld A Fillet Weld?

If we join two compartments of metals such that the two sheets are perpendicular or normal to each other, it is a fillet weld. So, a socket weld is a fillet weld. In this weld, the welder joins the sheets at an angle to each other.

How Many Passes On A Socket Weld?

The minimum number of passes required for a durable and sturdy socket weld are two. Two layers are best for a socket weld and enhance the sturdiness of the weld. In case one layer of weld deteriorates, the other layer will prevent any leakage.

How Do You Weld A Socket?

To weld a socket, you need to insert the fitting into the secluded region of the valve, pipe, or flange. After inserting the fittings, you can weld both the fitting and the pipelines together. By welding in such a way, the integrity of the weld increases many times.

Last Updated on October 25, 2021 by weldinghubs

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