What is Socket Weld Flange?

Socket weld flanges are a type of flange that is attached to a pipe by welding it to the end of the pipe. The socket weld flange has a recessed area that the end of the pipe fits into, and the flange is then welded around the perimeter of the socket. 

Socket weld flanges are used in applications where there is a need for high-pressure or high-temperature connections. Socket weld flanges are typically used in smaller pipe sizes and are often found in piping systems that are under 2 inches in diameter. 

Socket weld flanges are commonly used in industries such as petrochemical, chemical, and oil and gas. Socket weld flanges provide a strong and reliable connection that is able to withstand high pressures and temperatures, making them a popular choice for many industrial applications.

Socket weld flanges are designed for use in small diameter, high pressure piping systems. They are similar to slip-on flanges, but instead of having an outside diameter that slips over the pipe, the pipe is inserted into the socket of the flange. The socket itself is welded to the pipe, providing a strong, leak-resistant joint. Socket weld flanges are often used in applications where the fluid or gas being transported is at a high temperature or under high pressure, as they provide a more secure and stable connection than other types of flanges.

The ASME B16.5 standard says how big a Socket Weld Flange should be. This standard also says how flanges should be made and how much pressure they can hold. The diameter of the flange, the diameter of the bolt circle, the number of bolt holes, and the diameter of the bolt holes are the most important parts of a Socket Weld Flange.

The diameter of the flange is the overall size of the flange and is measured from edge to edge. The diameter of the circle that the bolt holes make is the bolt circle diameter. Socket Weld Flanges can have anywhere from 4 to 12 bolt holes. Most of the time, there are 4 bolt holes. The bolt hole diameter is the size of the holes that the bolts go through to connect the flange to the pipe.

It’s important to know that the ASME B16.5 standard has rules for Socket Weld Flanges in sizes ranging from NPS 1/2 to NPS 24. For flanges bigger than NPS 24, you may need to add more specifications.

In short, the ASME B16.5 standard tells us how to measure Socket Weld Flanges, including the diameter of the flange, the diameter of the bolt circle, the number of bolt holes, and the diameter of the bolt holes. These measurements are very important for making sure that a Socket Weld Flange is installed and works right in a high-pressure piping system.

Socket Weld Flange Dimensions (ASME B16.5)

Socket weld flanges are available in various sizes and dimensions, as per the ASME B16.5 standard. The dimensions for socket weld flanges are specified in this standard, with sizes ranging from 1/2″ to 3″. The flanges are available in various pressure classes, ranging from 150 to 2500. The standard provides detailed information about the dimensions, such as the diameter of the flange, the thickness of the flange, the diameter of the bolt circle, and the number of bolt holes. It is important to select the right size and pressure class of the socket weld flange, based on the specific application requirements. The dimensions specified in the ASME B16.5 standard ensure that the socket weld flanges are compatible with other ASME B16.5 flanges and fittings.

Socket Weld Flange Dimensions – Class 150 to Class 1500

The dimensions of socket weld flanges vary depending on the class of flange. Below are the dimensions of socket weld flanges according to ASME B16.5 for classes 150 to 1500:

  • Class 150: The socket weld flange has a nominal size ranging from 1/2 to 24 inches (DN 15 to DN 600), an outside diameter of 3.5 to 32 inches (88.9 to 812.8 mm), a raised face diameter of 2.38 to 25.5 inches (60.5 to 647.7 mm), a thickness of 0.44 to 2.75 inches (11.2 to 69.8 mm), and a bore diameter of 0.62 to 23.8 inches (15.7 to 603.3 mm).
  • Class 300: The socket weld flange has a nominal size ranging from 1/2 to 24 inches (DN 15 to DN 600), an outside diameter of 3.5 to 32 inches (88.9 to 812.8 mm), a raised face diameter of 2.38 to 25.5 inches (60.5 to 647.7 mm), a thickness of 0.56 to 3.25 inches (14.2 to 82.6 mm), and a bore diameter of 0.62 to 23.8 inches (15.7 to 603.3 mm).
  • Class 600: The socket weld flange has a nominal size ranging from 1/2 to 24 inches (DN 15 to DN 600), an outside diameter of 3.5 to 32 inches (88.9 to 812.8 mm), a raised face diameter of 2.38 to 25.5 inches (60.5 to 647.7 mm), a thickness of 0.69 to 3.88 inches (17.5 to 98.6 mm), and a bore diameter of 0.62 to 23.8 inches (15.7 to 603.3 mm).
  • Class 900: The socket weld flange has a nominal size ranging from 1/2 to 12 inches (DN 15 to DN 300), an outside diameter of 3.5 to 21.25 inches (88.9 to 539.8 mm), a raised face diameter of 2.38 to 18.75 inches (60.5 to 476.3 mm), a thickness of 0.94 to 4.38 inches (23.9 to 111.3 mm), and a bore diameter of 0.62 to 11.75 inches (15.7 to 298.5 mm).
  • Class 1500: The socket weld flange has a nominal size ranging from 1/2 to 12 inches (DN 15 to DN 300), an outside diameter of 3.5 to 21.25 inches (88.9 to 539.8 mm), a raised face diameter of 2.38 to 18.75 inches (60.5 to 476.3 mm), a thickness of 1.25 to 5.75 inches (31.8 to 146.1 mm), and a bore diameter of 0.62 to 11.75 inches (15.7 to 298.5 mm).
SOCKET WELD FLANGE DIMENSIONS IN INCHES
Class 150 Socket Neck Flange Dimensions

Dimensions of a socket weld flange class 150 (in inches)

Socket Weld Class 150 (in Inch)
NPSIDODBolt Circle (BC)Raised Face (R)Raised Face (RF)HDID 2*Raised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.88″3.50″2.38″1.38″.063″1.19″.38″0.62″.62″.38″.56″.62″4
3/4″1.09″3.88″2.75″1.69″.063″1.50″.44″0.82″.62″.44″.56″.62″4
1″1.36″4.25″3.12″2.00″.063″1.94″.50″1.05″.69″.50″.63″.62″4
1-1/4″1.70″4.62″3.50″2.50″.063″2.31″.56″1.38″.81″.56″.75″.62″4
1-1/2″1.97″5.00″3.88″2.88″.063″2.56″.62″1.61″.88″.62″.82″.62″4
2″2.44″6.00″4.75″3.62″.063″3.06″.69″2.07″1.00″.69″.94″.75″4
2-1/2″2.94″7.00″5.50″4.12″.063″3.56″.75″2.47″1.12″.82″1.06″.75″4
3″3.57″7.50″6.00″5.00″.063″4.25″.81″3.07″1.19″.88″1.13″.75″4
3-1/2″4.07″8.50″7.00″5.50″.063″4.81″.88″3.55″1.25″.88″1.19″.75″8
4″4.57″9.00″7.50″6.19″.063″5.31″.94″4.03″1.31″.88″1.25″.75″8
5″5.66″10.00″8.50″7.31″.063″6.44″.94″5.05″1.44″.88″1.38″.88″8
6″6.72″11.00″9.50″8.50″.063″7.56″1.06″6.07″1.56″.94″1.50″.88″8
8″8.72″13.50″11.75″10.62″.063″9.69″1.25″7.98″1.75″1.06″1.69″.88″8
10″10.88″16.00″14.25″12.75″.063″12.00″1.31″10.02″1.94″1.13″1.88″1.00″12
12″12.88″19.00″17.00″15.00″.063″14.38″1.56″12.00″2.19″1.19″2.13″1.00″12
14″14.14″21.00″18.75″16.25″.063″15.75″1.63″13.25″2.25″1.32″2.19″1.12″12
16″16.16″23.50″21.25″18.50″.063″18.00″1.75″15.25″2.50″1.38″2.44″1.12″16
18″18.18″25.00″22.75″21.00″.063″19.88″1.94″17.25″2.69″1.50″2.63″1.25″16
20″20.20″27.50″25.00″23.00″.063″22.00″2.13″19.25″2.88″1.63″2.83″1.25″20
22″22.22″29.50″27.25″25.25″.063″24.25″2.38″21.25″3.13″1.75″3.07″1.38″20
24″24.25″32.00″29.50″27.25″.063″26.12″2.50″23.25″3.25″1.82″3.19″1.38″20
Class 300 Socket Neck Flange Dimensions

Dimensions of socket weld flange class 300 (in inches)

Socket Weld Class 300 (in Inch)
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HDID 2*Raised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.88″3.75″2.62″1.38″.063″1.50″.38″0.62″0.88″0.50″0.82″0.62″4
3/4″1.09″4.62″3.25″1.69″.063″1.88″.44″0.82″1.00″.056″0.94″0.75″4
1″1.36″4.88″3.50″2.00″.063″2.12″.50″1.05″1.06″0.63″1.00″0.75″4
1-1/4″1.70″5.25″3.88″2.50″.063″2.50″.56″1.38″1.06″0.69″1.00″0.75″4
1-1/2″1.97″6.12″4.50″2.88″.063″2.75″.62″1.61″1.19″0.75″1.13″0.88″4
2″2.44″6.50″5.00″3.62″.063″3.31″.69″2.07″1.31″0.82″1.25″0.75″8
2-1/2″2.94″7.50″5.88″4.12″.063″3.94″.75″2.47″1.50″0.94″1.44″0.88″8
3″3.57″8.25″6.62″5.00″.063″4.62″.81″3.07″1.69″1.06″1.63″0.88″8
Class 600 Socket Neck Flange Dimensions

Dimensions of socket weld flanges class 600 (in inches)

Socket Weld Class 600 (in Inch)
FLANGE
NPS
IDODBolt Circle (BC)Raised Face (R)Raised Face (RF)HDID 2*Raised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.88″3.75″2.62″1.38″.250″1.50″.38″0.55″1.13″0.56″0.88″0.62″4
3/4″1.09″4.62″3.25″1.69″.250″1.88″.44″0.74″1.25″0.62″1.00″0.75″4
1″1.36″4.88″3.50″2.00″.250″2.12″.50″0.96″1.31″0.69″1.06″0.75″4
1-1/4″1.70″5.25″3.88″2.50″.250″2.50″.56″1.28″1.37″0.81″1.12″0.75″4
1-1/2″1.97″6.12″4.50″2.88″.250″2.75″.62″1.50″1.50″0.88″1.25″0.88″4
2″2.44″6.50″5.00″3.62″.250″3.31″.69″1.94″1.69″1.00″1.44″0.75″8
2-1/2″2.94″7.50″5.88″4.12″.250″3.94″.75″2.32″1.87″1.12″1.62″0.88″8
3″3.57″8.25″6.62″5.00″.250″4.62″.81″2.90″2.06″1.25″1.81″0.88″8
Class 900 Socket Neck Flange Dimensions
Class 900 Socket Neck Flange Dimensions
Nominal
Pipe Size
Outside
diameter of
flange
(D)
Thick of
flange
(B)
Diameter of
Hub at base
(A)
Diameter of
raised face
(G)
Length
thru Hub
(H)
Dia of
bore
(ID)
No of
holes
Dia of
holes
(L)
Dia of
bolts
Diam of
bolt circle
(K)
Approx
weight
kg
1/2 120.7 22.4 35.1 38.1 31.8 22.4 4 22.4 3/4 82.6 2
3/4 130 25.4 42.9 44.5 35.1 27.7 4 22.4 3/4 88.9 2
1 149.4 28.4 50.8 52.3 41.1 34.5 4 25.4 7/8 101.6 4
1-1/4 158.8 28.4 63.5 63.5 41.1 43.2 4 25.4 7/8 111.3 4
1-1/2 177.8 31.8 73.2 69.9 44.5 49.5 4 28.4 1 124 5
2 215.9 38.1 91.9 104.6 57.2 62 8 25.4 7/8 165.1 11
2-1/2 244.3 41.1 104.6 124 63.5 74.7 8 28.4 1 190.5 16
3 241.3 38.1 127 127 53.8 90.7 8 25.4 7/8 190.5 12
4 292.1 44.5 157.2 158.8 69.9 116.1 8 31.8 1-1/8 235 24
5 349.3 50.8 185.7 190.5 79.2 143.8 8 35.1 1-1/4 279.4 38
6 381 55.6 215.9 235 85.9 170.7 31.8 12 1-1/8 317.5 50
8 469.9 63.5 269.7 298.5 101.6 221.5 12 38.1 1-3/8 393.7 77
10 546.1 69.9 323.9 368.3 108 276.4 16 38.1 1-3/8 469.9 111
12 609.6 79.2 381 419.1 117.3 327.2 20 38.1 1-3/8 533.4 147
14 641.4 85.9 412.8 450.9 130 359.2 20 41.1 1-1/2 558.8 181
16 704.9 88.9 469.9 508 133.4 410.5 20 44.5 1-5/8 41.3 616
18 787.4 101.6 533.4 565.2 152.4 461.8 20 50.8 1-7/8 685.8 272
20 857.3 108 584.2 622.3 158.8 513.1 20 53.8 2 749.3 331
24 1041.4 139.7 692.2 749.3 203.2 616 20 66.5 2-1/2 901.7 635
SOCKET WELD CLASS 1500 (IN INCH)

Dimensions of socket weld flange class 1500 (in inches)

Socket Weld Class 1500 (in Inch)
SOCKET WELD FLANGE DIMENSIONS IN MILLIMETERS

SOCKET WELD CLASS 150 (IN MM)

Socket weld flange dimensions class 150 in millimeters (ASME B16.5)

Socket Weld Class 150 (in Mm)
Size
inch
D
mm
X
mm
G
mm
t
mm
B1
mm
B2
mm
T2
mm
Y
mm
1/28930.235.111.215.722.415.79.7
3/49938.142.912.720.827.715.711.2
110849.350.814.226.734.517.512.7
11758.763.515.735.143.220.614.2
12765.073.217.540.949.522.415.7
215277.791.919.152.662.025.417.5
17890.4104.622.462.774.728.419.1
3191108.0127.023.978.090.730.220.6
216122.2139.723.990.2103.431.822.4
4229134.9157.223.9102.4116.133.323.9
5254163.6185.723.9128.3143.836.623.9
6279192.0215.925.4154.2170.739.626.9
8343246.1269.728.4202.7221.544.531.8
10406304.8323.930.2254.5276.449.333.3
12483365.3381.031.8304.8327.255.639.6
14533400.1412.835.1336.6359.257.241.4
16597457.2469.936.6387.4410.563.544.5
18635505.0533.439.6438.2461.868.349.3
20699558.8584.242.9489.0513.173.254.1
24813663.4692.247.8590.6616.082.663.5
SizeDrillingBolting
inchBolt circle
Diameter mm
Holes #Holes Dia. mmBolt Dia. inch.Length
FF Flange
Length
RF Flange
Length
RTJ Flange
1/260.5415.71/250.857.2
3/469.9415.71/250.863.5
179.2415.71/257.263.576.2
88.9415.71/257.269.982.6
98.6415.71/263.569.982.6
2120.7419.15/869.982.695.3
139.7419.15/876.288.9101.6
3152.4419.15/876.288.9101.6
177.8819.15/876.288.9101.6
4190.5819.15/876.288.9101.6
5215.9822.43/482.695.3108.0
6241.3822.43/482.6101.6114.3
8298.5822.43/488.9108.0120.7
10362.01225.47/8101.6114.3127.0
12431.81225.47/8101.6120.7133.4
14476.31228.41114.3133.4146.1
16539.81628.41114.3133.4146.1
18577.91631.811/8127.0146.1158.8
20635.02031.811/8139.7158.8171.5
24749.32035.1152.4171.5184.2
SOCKET WELD CLASS 300 (IN MM)

Socket weld flange dimensions class 300 in millimeters (ASME B16.5)

Socket Weld Class 300 (in Mm)
Size
inch
D
mm
X
mm
G
mm
t
mm
B1
mm
B2
mm
T2
mm
Y
mm
1/29538.135.114.215.722.422.49.7
3/411747.842.915.720.827.725.411.2
112453.850.817.526.734.526.912.7
13363.563.519.135.143.226.914.2
15569.973.220.640.949.530.215.7
216584.191.922.452.662.033.317.5
191100.1104.625.462.774.738.119.1
3210117.3127.028.478.090.742.920.6
229133.4139.730.290.2103.444.522.4
4254146.1157.231.8102.4116.147.823.9
5279177.8185.735.1128.3143.850.823.9
6318206.2215.936.6154.2170.752.326.9
8381260.4269.741.1202.7221.562.031.8
10445320.5323.947.8254.5276.466.533.3
12521374.7381.050.8304.8327.273.239.6
14584425.5412.863.8336.6359.276.241.4
16648482.6469.957.2387.4410.582.644.5
18711533.4533.460.5438.2461.888.949.3
20775587.2584.263.5489.0513.195.354.1
24914701.5692.269.9590.6616.0106.463.5
SizeDrillingBolting
inchBolt circle
Diameter mm
Holes #Holes Dia. mmBolt Dia. inch.Length
FF Flange
Length
RF Flange
Length
RTJ Flange
1/266.5415.71/257.263.576.2
3/482.6419.15/863.576.288.9
188.9419.15/863.576.288.9
98.6419.15/869.982.695.3
114.3422.43/476.288.9101.6
2127.0819.15/876.288.9101.6
149.4822.43/482.6101.6114.3
3168.1822.43/488.9108.0120.7
184.2822.43/495.3108.0127.0
4200.2822.43/495.3114.3127.0
5235.0822.43/4108.0120.7133.4
6269.71222.43/4108.0120.7139.7
8330.21225.47/8120.7139.7152.4
10387.41628.41139.7158.8171.5
12450.91631.811/8146.1171.5184.2
14514.42031.811/8158.8177.8190.5
16571.52035.1165.1190.5203.2
18628.72435.1171.5196.9209.6
20685.82435.1184.2203.2222.3
24812.82441.1203.2228.6254.0
SOCKET WELD CLASS 600 (IN MM)

Socket weld flange dimensions class 600 in millimeters (ASME B16.5)

Socket Weld Class 600 (in Mm)
Size
inch
D
mm
X
mm
G
mm
t
mm
B1
mm
B2
mm
T2
mm
Y
mm
1/29538.135.114.2B36.10/.1922.422.49.7
3/411747.842.915.7B36.10/.1927.725.411.2
112453.850.817.5B36.10/.1934.526.912.7
13363.563.520.6B36.10/.1943.228.414.2
15569.973.222.4B36.10/.1949.531.815.7
216584.191.925.4B36.10/.1962.036.617.5
191100.1104.628.4B36.10/.1974.741.119.1
3210117.3127.031.8B36.10/.1990.746.020.6
229133.4139.735.1B36.10/.19103.449.322.4
4273152.4157.238.1B36.10/.19116.153.823.9
5330189.0185.744.5B36.10/.19143.860.523.9
6356222.3215.947.8B36.10/.19170.766.526.9
8419273.1269.755.6B36.10/.19221.576.231.8
10508342.9323.963.5B36.10/.19276.485.933.3
12559400.1381.066.5B36.10/.19327.291.939.6
14603431.8412.869.9B36.10/.19359.293.741.4
16686495.3469.976.2B36.10/.19410.5106.444.5
18743546.1533.482.6B36.10/.19461.8117.349.3
20813609.6584.288.9B36.10/.19513.1127.054.1
24940717.6692.2101.6B36.10/.19616.0139.763.5
SizeDrillingBolting
inchBolt circle
Diameter mm
Holes #Holes Dia. mmBolt Dia. inch.Length
FF Flange
Length
RF Flange
Length
RTJ Flange
1/266.5415.71/276.269.976.2
3/482.6419.15/888.982.688.9
188.9419.15/888.982.688.9
98.6419.15/895.388.995.3
114.3422.43/4108.0101.6108.0
2127.0819.15/8108.0101.6108.0
149.4822.43/4120.7114.3120.7
3168.1822.43/4127.0120.7127.0
184.2825.47/8139.7133.4139.7
4215.9825.47/8146.1139.7146.1
5266.7828.41165.1158.8165.1
6292.11228.41171.5165.1171.5
8349.31231.811/8190.5184.2196.9
10431.81635.1215.9209.6215.9
12489.02035.1222.3215.9222.3
14527.12038.113/8235.0228.6235.0
16603.32041.1254.0247.7254.0
18654.12044.515/8273.1266.7273.1
20723.92444.515/8285.8279.4292.1
24838.22450.817/8330.2323.9336.6
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