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.
| ANSI FLANGES WEIGHT (KGS) | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nom Pipe Size |
150# | 300# | 600# | 900# | 1500# | 2500# | ||||||||||||
| WN | S/O | B/K | WN | S/O | B/K | WN | S/O | B/K | WN | S/O | B/K | WN | S/O | B/K | WN | S/O | B/K | |
| 1/2'' | 0.7 | 0.4 | 0.5 | 0.8 | 0.7 | 0.8 | 0.9 | 0.8 | 0.8 | 2.1 | 1.8 | 1.9 | 2.1 | 1.8 | 1.9 | 3.2 | 3 | 3 |
| 3/4'' | 0.8 | 0.7 | 0.8 | 1.4 | 1.2 | 1.2 | 1.6 | 1.4 | 1.4 | 2.7 | 2.4 | 2.7 | 2.7 | 2.4 | 2.7 | 3.6 | 4 | 4.5 |
| 1'' | 1.1 | 0.8 | 0.9 | 1.7 | 1.4 | 1.5 | 1.9 | 1.7 | 1.7 | 3.9 | 3.6 | 3.7 | 3.9 | 3.6 | 3.7 | 5.4 | 5 | 5 |
| 1.1/4'' | 1.5 | 1.2 | 1.3 | 2.2 | 1.8 | 2 | 2.6 | 2.1 | 2.4 | 4.5 | 4.1 | 4.3 | 4.5 | 4.1 | 4.3 | 7.8 | 8 | 8 |
| 1.1/2'' | 1.8 | 1.4 | 1.6 | 3.2 | 2.7 | 2.9 | 3.6 | 3.1 | 3.4 | 6.2 | 5.4 | 5.9 | 6.2 | 5.4 | 5.9 | 11.5 | 11 | 11 |
| 2'' | 2.7 | 2.2 | 2.6 | 3.6 | 3.2 | 3.5 | 4.7 | 3.9 | 4.4 | 11.3 | 10.5 | 11.3 | 11.3 | 10.5 | 11.3 | 19 | 17 | 17 |
| 2.1/2'' | 4.4 | 3.5 | 4.1 | 5.4 | 4.5 | 5.3 | 4.8 | 5.4 | 6.8 | 16.3 | 15.8 | 16 | 16.3 | 15.8 | 16 | 24 | 25 | 25 |
| 3'' | 5.2 | 3.8 | 5.1 | 7.3 | 5.9 | 7.2 | 8.7 | 7.3 | 8.9 | 15 | 12.3 | 16.8 | 21 | 21.5 | 19.5 | 42.6 | 38 | 39 |
| 3-1/2'' | 6.4 | 5 | 6.5 | 8.9 | 7.5 | 9.2 | 11.6 | 9 | 12.7 | - | - | - | - | - | - | - | - | - |
| 4'' | 7.5 | 5.6 | 7.5 | 11.8 | 10 | 12.2 | 18.4 | 16.5 | 18.6 | 24 | 23.2 | 24.5 | 31.8 | 31 | 33 | 64 | 58 | 60 |
| 5'' | 9.2 | 6.5 | 9.2 | 16 | 12.5 | 16 | 31 | 28.5 | 30.8 | 38.5 | 37.5 | 39.5 | 59 | 58.8 | 60 | 111 | 95 | 101 |
| 6'' | 11.0 | 8.1 | 11.8 | 20.2 | 16.5 | 22 | 37 | 36.2 | 38 | 50 | 48.3 | 51.5 | 72 | 74 | 75 | 171 | 146 | 156 |
| 8'' | 18.4 | 13 | 20.4 | 31.2 | 25.5 | 36 | 54.5 | 51.5 | 62.2 | 85 | 75 | 89 | 124 | 112 | 125 | 261 | 220 | 242 |
| 10'' | 25.5 | 18.4 | 31 | 44.3 | 35 | 55 | 98.5 | 76.2 | 102 | 123 | 110 | 131 | 207 | 184 | 215 | 485 | 420 | 465 |
| 12'' | 37 | 28.5 | 47 | 63.5 | 52 | 82.5 | 105 | 89.5 | 132 | 168 | 146 | 187 | 306 | 264 | 316 | 698 | 590 | 665 |
| 14'' | 51 | 37.5 | 60 | 86 | 73 | 108 | 150 | 102 | 158 | 198 | 172 | 224 | 416 | - | - | - | - | - |
| 16'' | 61.5 | 44.5 | 61 | 112 | 88 | 139 | 177 | 150 | 225 | 225 | 192 | 259 | 567 | - | - | - | - | - |
| 18'' | 71.5 | 54 | 93 | 141 | 115 | 178 | 228 | 180 | 285 | 318 | 272 | 383 | 736 | - | - | - | - | - |
| 20'' | 85 | 72 | 127 | 173 | 139 | 228 | 285 | 231 | 365 | 376 | 330 | 482 | 929 | - | - | - | - | - |
| 24'' | 119 | 95 | 190 | 248 | 212 | 350 | 372 | 330 | 532 | 680 | 632 | 905 | 1504 | - | - | - | - | - |
Weldneck flanges
Weldneck flanges have drilled wall thickness which is of equally same dimension existing for matching pipe. Bore will be larger if the pipe is lighter and opposite will be true if pipe is heavier and the bore will be small. Erosion as well as turbulence is significantly reduced in pipeline as bores of flange & pipe match. Due to these reasons weldneck flanges are chosen for critical applications where high pressure and hot-cold temperatures are prevalent. The different kinds of weldneck flanges available are:
