Socket weld fittings are a common pipe connector, with a design feature of a socket (large mouth) on one end and a spigot (small mouth) on the other end. After the spigot is inserted into the socket, the connection and sealing are achieved by welding, bonding, sealing rings or other mechanical methods. This connection method is very common in many pipeline systems.
Socket weld fittings are widely used in various industries, such as petroleum, chemical, pharmaceutical, water treatment and other industrial fields, as well as pipeline connections in buildings and other structures.
ASME B16.11 Socket Weld Fittings Specification
| Type | Elbow, Tee, Cross, Coupling, Cap, Lateral |
| Size Range | 1/8″- 4″ / DN6 – DN100 |
| Pressure Rating | Class 3000LBS, 6000Lbs, 9000lbs. |
| Carbon Steel | ASTM A105 / A105N, ASTM A350 LF2, A694 F42 / 46 / 56 / 60 / 65 |
| Alloy Steel | ASTM A182 F11 / 12 / 22 / 5 / 9 / 91 / 92 / 22 |
| Stainless Steel | ASTM A182 F304 / 304L / 304H, 316 / 316L, 321, 310S, 317, 347, 904L |
| Duplex Stainless Steel | ASTM A182 F51, F53, F44 |
Types of Socket Weld Fittings
Socket Weld Fittings types include Elbow, Tee, Cross, Coupling, Union, Cap .
Socket Weld Elbow:
The socket elbow is used to change the direction of the pipeline, with different angles such as 90 degrees, 45 degrees, and 180 degrees. In the pipeline system, choosing a socket elbow with a suitable angle according to the actual layout requirements can enable the pipeline to bypass obstacles smoothly or achieve connections in different directions.
Socket Weld Tee
Socket tee: Socket tee is divided into straight tee and reducing tee. The three interfaces of the straight tee are perpendicular to each other, which is used to divide a main pipe into two branches or merge two branches into one main pipe; the interface of the reducing tee has a certain angle, which is suitable for some special angle branch connections.
Socket Weld Cross
The socket cross is used to connect four pipelines. Compared with the tee, it can achieve more complex pipeline connections and medium flow control. In some large chemical plants or municipal pipe networks, the socket cross can connect multiple pipeline systems together to achieve flexible transportation and deployment of the medium.
Socket Weld Coupling
The coupling is a pipe fitting used to connect two pipes, usually made of metal or plastic. Its structural characteristics are that one end is a socket and the other end is a spigot.
Socket Weld Cap
A pipe cap is a ASME B16.11 socket weld pipe fitting used to close the end of a pipe. It has a simple structure, one end is open and is used to be put on the end of the pipe, and the other end is a closed end.
Socket Weld Union
A union is a pipe connector that can be easily disassembled and assembled, consisting of a male connector, a female connector and a sealing gasket.
Tolerance for Socket Weld Fittings
| Nominal Size | All Fittings | Elbows, Tees & Crosses | Couplings | Half- Couplings | Reducer Inserts | Unions | ||||
| Socket Bore Dia. | Bore Dia. of Fittings | Center to Bottom of Socket | Laying Lengths | Laying Lengths | Laying Length | Shank Dia. | Length | Laying Length | ||
| DN | NPS | B | D | A H | E | F | A | SD | SL | E |
| 6~8 | 1/8~1/4 | +0.4 0 | +1.5 0 | ± 1.0 | ± 1.5 | ± 1.0 | +1.5 0 | ± 0.25 | 0 -1.5 | ± 1.5 |
| 10~20 | 3/8~3/4 | +0.4 0 | +1.5 0 | ± 1.5 | ± 3.0 | ± 1.5 | +1.5 0 | ± 0.25 | 0 -1.5 | ± 3.0 |
| 25~40 | 1~11/2 | +0.4 0 | +1.5 0 | ± 2.0 | ± 4.0 | ± 2.0 | +2.0 0 | ± 0.25 | 0 -2.0 | ± 4.0 |
| 50 | 2 | +0.5 0 | +1.5 0 | ± 2.0 | ± 4.0 | ± 2.0 | +2.0 0 | ± 0.5 | 0 -2.0 | ± 4.0 |
| 65~80 | 21/2~3 | +0.5 0 | +3.0 0 | ± 2.5 | ± 5.0 | ± 2.5 | +2.5 0 | ± 0.5 | 0 -2.5 | ± 5.0 |
| 100 | 4 | +0.5 0 | +3.0 0 | ± 2.5 | ± 5.0 | ± 2.5 | +2.5 0 | ± 0.7 | 0 -2.5 | – |
Common Materials for Socket Weld Fittings
Carbon steel Socket Weld Fittings:
ASTM A105 / A105N,ASTM A350 LF2 / LF3, A694 F42 / 46 / 52 / 56 / 65 / 70
Carbon steel is one of the most common manufacturing materials, widely used in general industrial piping and civil water supply and drainage piping due to its lower cost and higher strength. In petrochemical, electric power, metallurgy and other industries, carbon steel socket pipe fittings can be used to transport water, steam, oil and other media. For example, in the ordinary factory cooling water piping system, carbon steel socket elbow, tee and other fittings can effectively connect the various sections of piping to ensure the smooth transportation of cooling water.
Stainless Steel Socket Weld Fittings:
A182 F304/304L/304H – F316/316L – F317 – F310S – F321 – F347 – F904L
Stainless steel has excellent corrosion resistance, high temperature resistance and sanitary properties, suitable for occasions with high corrosion resistance requirements, such as food and beverage, pharmaceutical, chemical and other industries. In the food processing workshop piping system, stainless steel socket fittings can ensure that the transported materials are not contaminated; in chemical production, stainless steel socket fittings can resist the erosion of corrosive media, to protect the piping system for long-term stable operation.
Alloy Steel Socket Fittings:
Alloy Steel: ASTM A182 F5 / F9 / F11 / F12 / F22 / F91 / F92
Alloy steel by adding different alloying elements, with high strength, high toughness, high temperature resistance, low temperature resistance and other special properties, commonly used in high temperature, high pressure, high corrosive and other harsh conditions. In the petroleum refining hydrogenation device, natural gas transmission of high-pressure pipeline system, alloy steel socket fittings with its good overall performance, can effectively withstand high temperatures, high pressures and medium corrosion, to ensure the safe operation of the pipeline system.
Applications of Socket weld Fittings
Building water supply and drainage system: widely used in residential and commercial buildings for hot and cold water supply piping, as well as internal drainage and sewage piping.
Chemical and petrochemical industry: in the transportation of corrosive fluids or high sealing requirements of the pipeline, stainless steel, alloy steel socket weld fittings are particularly common, especially in small diameter instrumentation pipelines and high-pressure systems.
Municipal engineering: used in urban water supply, sewage and rainwater pipe network.
Fire-fighting system: socket threaded or socket welded fittings are commonly used in fire-fighting water pipelines to ensure the reliability of the connection.
Power industry: socket weld fittings are also used in circulating water, desulphurization pipelines and all kinds of auxiliary pipelines in power plants.
Agricultural irrigation: PVC, PE and other plastic socket weld fittings are widely used in agricultural irrigation systems due to their cost-effectiveness and easy installation.