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
