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Class 300 Weld Neck Flanges

Weld neck flanges are flanges in which welding is done on the neck of the flange thus giving its name weld neck flange. The design of weld neck flange is such that it reduces stress coming on the base of flange by transferring it on pipe thus transferring heavy concentration of pressure only on flange. The I.D of both pipe and flange matches there by reducing turbulence and erosion in the pipe due to continuous flow and stagnating particulates. Weld neck flanges are used in critical high pressure areas thus making it the most preferred butt weld flanges amongst all flanges. We are amongst the biggest exporters of weld neck flanges in India.

DIMENSIONS OF CLASS 300 FLANGES (ANSI B 16.5) (in mm)
Nominal
Pipe Size
Flange
Dia
'O'
Dia of
Bolt Circle
'A'
Dia of Bolt Holes
'D'
No. of
Holes
Thk of Flange
'C'
Diameter at Weld Bevel Dia of Hub
'E'
Length Through Hub Bore 'B' Dia of
R/F
R
Depth of
Socket
F
Length
of
Threading
S/O & S/W
Y
W/N
Y
L/J
Y
S/O & S/W
B
L/J
B
1/2'' 15 95.2 66.7 15.9 4 14.3 21.3 38.1 22.2 52.4 22.2 22.3 22.9 34.9 9.5 15.9
3/4'' 20 117.5 82.5 19.0 4 15.9 26.7 47.6 25.4 57.1 25.4 27.7 28.2 42.9 11.1 15.9
1'' 25 123.8 88.9 19.0 4 17.5 33.5 54.0 27.0 61.9 27.0 34.5 35.0 50.8 12.7 17.5
1 ¼'' 32 133.3 98.4 19.0 4 19.0 42.2 63.5 27.0 65.1 27.0 43.2 43.7 63.5 14.3 20.6
1 ½'' 40 155.6 114.3 22.2 4 20.6 48.3 69.8 30.2 68.3 30.2 49.5 50.0 73.0 15.9 22.2
2'' 50 165.1 127.0 19.0 8 22.2 60.4 84.1 33.3 69.8 33.3 62.0 62.5 92.1 17.5 25.4
2 ½'' 65 190.5 149.2 22.2 8 25.4 73.1 100.0 38.1 76.2 38.1 74.7 75.4 104.8 19.0 28.6
3'' 80 209.5 168.3 22.2 8 28.6 88.9 117.5 42.9 79.4 42.9 90.7 91.4 127.0 20.6 30.2
3 ½'' 90 228.5 184.2 22.2 8 30.2 101.6 133.4 44.5 81.0 44.5 103.4 104.1 140.0 20.6 31.7
4'' 100 254.0 200.0 22.2 8 31.8 114.3 146.0 47.6 85.7 47.6 116.1 116.8 157.2 23.8 33.3
5'' 125 279.4 234.9 22.2 8 34.9 141.2 177.8 50.8 98.4 50.8 143.8 144.5 185.7 - 36.5
6'' 150 317.5 269.9 22.2 12 36.5 168.4 206.4 52.4 98.4 52.4 170.7 171.4 215.9 - 39.7
8'' 200 381.0 330.2 25.4 12 41.3 219.2 260.3 61.9 111.1 61.9 221.5 222.2 269.9 - 44.4
10'' 250 444.5 387.3 28.6 16 47.6 273.0 320.7 66.7 117.5 95.2 276.3 277.4 323.8 - 49.2
12'' 300 520.7 450.8 31.7 16 50.8 323.8 374.6 73.0 130.2 101.6 327.1 328.2 381.0 - 55.6
14'' 350 584.2 514.3 31.7 20 54.0 355.6 425.4 76.2 142.9 111.1 359.1 360.2 412.7 - 57.1
16'' 400 647.7 571.5 34.9 20 57.2 406.4 482.6 82.5 146.0 120.6 410.5 411.2 469.9 - 63.5
18'' 450 711.2 628.5 34.9 24 60.3 457.2 533.4 88.9 158.7 130.2 461.8 462.3 533.4 - 68.3
20'' 500 774.7 685.8 34.9 24 63.5 508.0 587.4 95.2 161.9 139.7 513.1 514.3 584.2 - 73.0
24'' 600 914.4 812.8 41.3 24 69.8 609.6 701.7 106.4 168.3 152.4 615.9 615.9 692.1 - 82.5

Note : Thickness 'C' is inclusive of Raised Face Thickness of 1.65 MM. For Class 300