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Carbon Steel Weld Neck Flanges Manufacturer and Supplier in India
A carbon steel weld neck flange is a forged flange identified by its long tapered hub, which is butt welded directly to the pipe end so the flange, the weld and the pipe wall form one continuous piece of steel. It is the flange type governed by ASME B16.5 and ASME B16.47, supplied in ASTM A105 forged grade, with ASTM A694 F42 to F70 available where a higher yield strength is required, across Class 150 through 2500 duty. Because the neck and the pipe are joined by a full penetration weld rather than a lighter fillet weld, a weld neck flange is the default choice for critical, high-pressure and high-temperature piping, and it is the most commonly specified flange type for Class 900 and above in critical or high-pressure service. Solitaire Overseas manufactures carbon steel weld neck flanges with full mill test certification, and hydrostatic testing, ultrasonic testing or third party inspection can be arranged on request.
Technical Data
Specifications of Carbon Steel Weld Neck Flanges
| Parameter | Specification |
|---|---|
Standard |
ASTM A105, ASTM A694, ASME B16.5, ASME B16.47 |
Size Range |
NPS 1/2 inch to 24 inch per ASME B16.5 (full dimension tables below); NPS 26 inch to 48 inch per ASME B16.47, dimensions on request |
Pressure Class |
Class 150, 300, 400, 600, 900, 1500, 2500 |
Facing |
Raised Face (RF) or Ring Type Joint (RTJ) |
Construction |
Forged, tapered hub, full penetration butt weld to pipe |
Testing |
Hydrostatic test, ultrasonic test, third party inspection on request |
Certification |
Mill Test Certificate EN 10204 3.1, 3.2 on request |
Chemical Compositions of Carbon Steel Weld Neck Flanges
| Grade | C max | Mn | P max | S max | Si |
|---|---|---|---|---|---|
A105 |
0.35 |
0.60 to 1.05 |
0.035 |
0.040 |
0.10 to 0.35 |
A694 F42 to F70 (heat analysis) |
0.30 |
1.60 max |
0.025 |
0.025 |
0.15 to 0.35 |
Mechanical Properties of Carbon Steel Weld Neck Flanges
| Grade | Tensile Strength min, MPa (ksi) | Yield Strength min, MPa (ksi) | Elongation min (%) |
|---|---|---|---|
A105 | 485 (70) | 250 (36) | 22 |
A694 F42 | 415 (60) | 290 (42) | 20 |
A694 F46 | 415 (60) | 315 (46) | 20 |
A694 F48 | 425 (62) | 330 (48) | 20 |
A694 F50 | 440 (64) | 345 (50) | 20 |
A694 F52 | 455 (66) | 360 (52) | 20 |
A694 F56 | 470 (68) | 385 (56) | 20 |
A694 F60 | 515 (75) | 415 (60) | 20 |
A694 F65 | 530 (77) | 450 (65) | 20 |
A694 F70 | 565 (82) | 485 (70) | 18 |
Carbon Steel Weld Neck Flanges Pressure Class
| Class | Approximate Rating at Ambient (psi) | Approximate Rating at Ambient (bar) |
|---|---|---|
150 |
285 |
20 |
300 |
740 |
51 |
400 |
990 |
68 |
600 |
1480 |
102 |
900 |
2220 |
153 |
1500 |
3705 |
255 |
2500 |
6170 |
425 |
Carbon Steel Weld Neck Flange Dimensions by Pressure Class
The carbon steel weld neck flanges comes in a different dimensions according to their pressure classes and the details information about this is listed below.
Class 150 Carbon Steel Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 90 | 9.6 | 30 | 21.3 | 46 | 60.3 | 4 | 1/2 | 5/8 | 55 |
| 3/4 | 20 | 100 | 11.2 | 38 | 26.7 | 51 | 69.9 | 4 | 1/2 | 5/8 | 65 |
| 1 | 25 | 110 | 12.7 | 49 | 33.4 | 54 | 79.4 | 4 | 1/2 | 5/8 | 65 |
| 1 1/4 | 32 | 115 | 14.3 | 59 | 42.2 | 56 | 88.9 | 4 | 1/2 | 5/8 | 70 |
| 1 1/2 | 40 | 125 | 15.9 | 65 | 48.3 | 60 | 98.4 | 4 | 1/2 | 5/8 | 70 |
| 2 | 50 | 150 | 17.5 | 78 | 60.3 | 62 | 120.7 | 4 | 5/8 | 3/4 | 85 |
| 2 1/2 | 65 | 180 | 20.7 | 90 | 73 | 68 | 139.7 | 4 | 5/8 | 3/4 | 90 |
| 3 | 80 | 190 | 22.3 | 108 | 88.9 | 68 | 152.4 | 4 | 5/8 | 3/4 | 90 |
| 3 1/2 | 90 | 215 | 22.3 | 122 | 101.6 | 70 | 177.8 | 8 | 5/8 | 3/4 | 90 |
| 4 | 100 | 230 | 22.3 | 135 | 114.3 | 75 | 190.5 | 8 | 5/8 | 3/4 | 90 |
| 5 | 125 | 255 | 22.3 | 164 | 141.3 | 87 | 215.9 | 8 | 3/4 | 7/8 | 95 |
| 6 | 150 | 280 | 23.9 | 192 | 168.3 | 87 | 241.3 | 8 | 3/4 | 7/8 | 100 |
| 8 | 200 | 345 | 27 | 246 | 219.1 | 100 | 298.5 | 8 | 3/4 | 7/8 | 110 |
| 10 | 250 | 405 | 28.6 | 305 | 273 | 100 | 362 | 12 | 7/8 | 1 | 115 |
| 12 | 300 | 485 | 30.2 | 365 | 323.8 | 113 | 431.8 | 12 | 7/8 | 1 | 120 |
| 14 | 350 | 535 | 33.4 | 400 | 355.6 | 125 | 476.3 | 12 | 1 | 1 1/8 | 135 |
| 16 | 400 | 595 | 35 | 457 | 406.4 | 125 | 539.8 | 16 | 1 | 1 1/8 | 135 |
| 18 | 450 | 635 | 38.1 | 505 | 457.2 | 138 | 577.9 | 16 | 1 1/8 | 1 1/4 | 145 |
| 20 | 500 | 700 | 41.3 | 559 | 508 | 143 | 635 | 20 | 1 1/8 | 1 1/4 | 160 |
| 24 | 600 | 815 | 46.1 | 663 | 610 | 151 | 749.3 | 20 | 1 1/4 | 1 3/8 | 170 |
Class 300 Carbon Steel Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 95 | 12.7 | 38 | 21.3 | 51 | 66.7 | 4 | 1/2 | 5/8 | 65 |
| 3/4 | 20 | 115 | 14.3 | 48 | 26.7 | 56 | 82.6 | 4 | 5/8 | 3/4 | 75 |
| 1 | 25 | 125 | 15.9 | 54 | 33.4 | 60 | 88.9 | 4 | 5/8 | 3/4 | 75 |
| 1 1/4 | 32 | 135 | 17.5 | 64 | 42.2 | 64 | 98.4 | 4 | 5/8 | 3/4 | 85 |
| 1 1/2 | 40 | 155 | 19.1 | 70 | 48.3 | 67 | 114.3 | 4 | 3/4 | 7/8 | 90 |
| 2 | 50 | 165 | 20.7 | 84 | 60.3 | 68 | 127 | 8 | 5/8 | 3/4 | 90 |
| 2 1/2 | 65 | 190 | 23.9 | 100 | 73 | 75 | 149.2 | 8 | 3/4 | 7/8 | 100 |
| 3 | 80 | 210 | 27 | 117 | 88.9 | 78 | 168.3 | 8 | 3/4 | 7/8 | 110 |
| 3 1/2 | 90 | 230 | 28.6 | 133 | 101.6 | 79 | 184.2 | 8 | 3/4 | 7/8 | 110 |
| 4 | 100 | 255 | 30.2 | 146 | 114.3 | 84 | 200 | 8 | 3/4 | 7/8 | 115 |
| 5 | 125 | 280 | 33.4 | 178 | 141.3 | 97 | 235 | 8 | 3/4 | 7/8 | 120 |
| 6 | 150 | 320 | 35 | 206 | 168.3 | 97 | 269.9 | 12 | 3/4 | 7/8 | 120 |
| 8 | 200 | 380 | 39.7 | 260 | 219.1 | 110 | 330.2 | 12 | 7/8 | 1 | 140 |
| 10 | 250 | 445 | 46.1 | 321 | 273 | 116 | 387.4 | 16 | 1 | 1 1/8 | 160 |
| 12 | 300 | 520 | 49.3 | 375 | 323.8 | 129 | 450.8 | 16 | 1 1/8 | 1 1/4 | 170 |
| 14 | 350 | 585 | 52.4 | 425 | 355.6 | 141 | 514.4 | 20 | 1 1/8 | 1 1/4 | 180 |
| 16 | 400 | 650 | 55.6 | 483 | 406.4 | 144 | 571.5 | 20 | 1 1/4 | 1 3/8 | 190 |
| 18 | 450 | 710 | 58.8 | 533 | 457 | 157 | 628.6 | 24 | 1 1/4 | 1 3/8 | 195 |
| 20 | 500 | 775 | 62 | 587 | 508 | 160 | 685.8 | 24 | 1 1/4 | 1 3/8 | 205 |
| 24 | 600 | 915 | 68.3 | 702 | 610 | 167 | 812.8 | 24 | 1 1/2 | 1 5/8 | 230 |
Class 400 Carbon Steel Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 95 | 14.3 | 38 | 21.3 | 52 | 66.7 | 4 | 1/2 | 5/8 | 75 |
| 3/4 | 20 | 115 | 15.9 | 48 | 26.7 | 57 | 82.6 | 4 | 5/8 | 3/4 | 90 |
| 1 | 25 | 125 | 17.5 | 54 | 33.4 | 62 | 88.9 | 4 | 5/8 | 3/4 | 90 |
| 1 1/4 | 32 | 135 | 20.7 | 64 | 42.2 | 67 | 98.4 | 4 | 5/8 | 3/4 | 95 |
| 1 1/2 | 40 | 155 | 22.3 | 70 | 48.3 | 70 | 114.3 | 4 | 3/4 | 7/8 | 110 |
| 2 | 50 | 165 | 25.4 | 84 | 60.3 | 73 | 127 | 8 | 5/8 | 3/4 | 110 |
| 2 1/2 | 65 | 190 | 28.6 | 100 | 73 | 79 | 149.2 | 8 | 3/4 | 7/8 | 120 |
| 3 | 80 | 210 | 31.8 | 117 | 88.9 | 83 | 168.3 | 8 | 3/4 | 7/8 | 125 |
| 3 1/2 | 90 | 230 | 35 | 133 | 101.6 | 86 | 184.2 | 8 | 7/8 | 1 | 140 |
| 4 | 100 | 255 | 35 | 146 | 114.3 | 89 | 200 | 8 | 7/8 | 1 | 140 |
| 5 | 125 | 280 | 38.1 | 178 | 141.3 | 102 | 235 | 8 | 7/8 | 1 | 145 |
| 6 | 150 | 320 | 41.3 | 206 | 168.3 | 103 | 269.9 | 12 | 7/8 | 1 | 150 |
| 8 | 200 | 380 | 47.7 | 260 | 219.1 | 117 | 330 | 12 | 1 | 1 1/8 | 170 |
| 10 | 250 | 445 | 54 | 321 | 273 | 124 | 387.4 | 16 | 1 1/8 | 1 1/4 | 190 |
| 12 | 300 | 520 | 57.2 | 375 | 323.8 | 137 | 450.8 | 16 | 1 1/4 | 1 3/8 | 205 |
| 14 | 350 | 585 | 60.4 | 425 | 355.6 | 149 | 514.4 | 20 | 1 1/4 | 1 3/8 | 210 |
| 16 | 400 | 650 | 63.5 | 483 | 406.4 | 152 | 571.5 | 20 | 1 3/8 | 1 1/2 | 220 |
| 18 | 450 | 710 | 66.7 | 533 | 457 | 165 | 628.6 | 24 | 1 3/8 | 1 1/2 | 230 |
| 20 | 500 | 775 | 69.9 | 587 | 508 | 168 | 685.8 | 24 | 1 1/2 | 1 3/4 | 240 |
| 24 | 600 | 915 | 76.2 | 702 | 610 | 175 | 812.8 | 24 | 1 3/4 | 1 7/8 | 265 |
Class 600 Carbon Steel Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 95 | 14.3 | 38 | 21.3 | 52 | 66.7 | 4 | 1/2 | 5/8 | 75 |
| 3/4 | 20 | 115 | 15.9 | 48 | 26.7 | 57 | 82.6 | 4 | 5/8 | 3/4 | 90 |
| 1 | 25 | 125 | 17.5 | 54 | 33.4 | 62 | 88.9 | 4 | 5/8 | 3/4 | 90 |
| 1 1/4 | 32 | 135 | 20.7 | 64 | 42.2 | 67 | 98.4 | 4 | 5/8 | 3/4 | 95 |
| 1 1/2 | 40 | 155 | 22.3 | 70 | 48.3 | 70 | 114.3 | 4 | 3/4 | 7/8 | 110 |
| 2 | 50 | 165 | 25.4 | 84 | 60.3 | 73 | 127 | 8 | 5/8 | 3/4 | 110 |
| 2 1/2 | 65 | 190 | 28.6 | 100 | 73 | 79 | 149.2 | 8 | 3/4 | 7/8 | 120 |
| 3 | 80 | 210 | 31.8 | 117 | 88.9 | 83 | 168.3 | 8 | 3/4 | 7/8 | 125 |
| 3 1/2 | 90 | 230 | 35 | 133 | 101.6 | 86 | 184.2 | 8 | 7/8 | 1 | 140 |
| 4 | 100 | 275 | 38.1 | 152 | 114.3 | 102 | 215.9 | 8 | 7/8 | 1 | 145 |
| 5 | 125 | 330 | 44.5 | 189 | 141.3 | 114 | 266.7 | 8 | 1 | 1 1/8 | 165 |
| 6 | 150 | 355 | 47.7 | 222 | 168.3 | 117 | 292.1 | 12 | 1 | 1 1/8 | 170 |
| 8 | 200 | 420 | 55.6 | 273 | 219.1 | 133 | 349.2 | 12 | 1 1/8 | 1 1/4 | 190 |
| 10 | 250 | 510 | 63.5 | 343 | 273 | 152 | 431.8 | 16 | 1 1/4 | 1 3/8 | 215 |
| 12 | 300 | 560 | 66.7 | 400 | 323.8 | 156 | 489 | 20 | 1 1/4 | 1 3/8 | 220 |
| 14 | 350 | 605 | 69.9 | 432 | 355.6 | 165 | 527 | 20 | 1 3/8 | 1 1/2 | 235 |
| 16 | 400 | 685 | 76.2 | 495 | 406.4 | 178 | 603.2 | 20 | 1 1/2 | 1 5/8 | 255 |
| 18 | 450 | 745 | 82.6 | 546 | 457 | 184 | 654 | 20 | 1 5/8 | 1 3/4 | 275 |
| 20 | 500 | 815 | 88.9 | 610 | 508 | 190 | 723.9 | 24 | 1 5/8 | 1 3/4 | 285 |
| 24 | 600 | 940 | 101.6 | 718 | 610 | 203 | 838.2 | 24 | 1 7/8 | 2 | 330 |
Class 900 Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 120 | 22.3 | 38 | 21.3 | 60 | 82.6 | 4 | 3/4 | 7/8 | 110 |
| 3/4 | 20 | 130 | 25.4 | 44 | 26.7 | 70 | 88.9 | 4 | 3/4 | 7/8 | 115 |
| 1 | 25 | 150 | 28.6 | 52 | 33.4 | 73 | 101.6 | 4 | 7/8 | 1 | 125 |
| 1 1/4 | 32 | 160 | 28.6 | 64 | 42.2 | 73 | 111.1 | 4 | 7/8 | 1 | 125 |
| 1 1/2 | 40 | 180 | 31.8 | 70 | 48.3 | 83 | 123.8 | 4 | 1 | 1 1/8 | 140 |
| 2 | 50 | 215 | 38.1 | 105 | 60.3 | 102 | 165.1 | 8 | 7/8 | 1 | 145 |
| 2 1/2 | 65 | 245 | 41.3 | 124 | 73 | 105 | 190.5 | 8 | 1 | 1 1/8 | 160 |
| 3 | 80 | 240 | 38.1 | 127 | 88.9 | 102 | 190.5 | 8 | 7/8 | 1 | 145 |
| 4 | 100 | 290 | 44.5 | 159 | 114.3 | 114 | 235 | 8 | 1 1/8 | 1 1/4 | 170 |
| 5 | 125 | 350 | 50.8 | 190 | 141.3 | 127 | 279.4 | 8 | 1 1/4 | 1 3/8 | 190 |
| 6 | 150 | 380 | 55.6 | 235 | 168.3 | 140 | 317.5 | 12 | 1 1/8 | 1 1/4 | 190 |
| 8 | 200 | 470 | 63.5 | 298 | 219.1 | 162 | 393.7 | 12 | 1 3/8 | 1 1/2 | 220 |
| 10 | 250 | 545 | 69.9 | 368 | 273 | 184 | 469.9 | 16 | 1 3/8 | 1 1/2 | 235 |
| 12 | 300 | 610 | 79.4 | 419 | 323.8 | 200 | 533.4 | 20 | 1 3/8 | 1 1/2 | 255 |
| 14 | 350 | 640 | 85.8 | 451 | 355.6 | 213 | 558.8 | 20 | 1 1/2 | 1 5/8 | 275 |
| 16 | 400 | 705 | 88.9 | 508 | 406.4 | 216 | 616 | 20 | 1 5/8 | 1 3/4 | 285 |
| 18 | 450 | 785 | 101.6 | 565 | 457 | 229 | 685.8 | 20 | 1 7/8 | 2 | 325 |
| 20 | 500 | 855 | 108 | 622 | 508 | 248 | 749.3 | 20 | 2 | 2 1/8 | 350 |
| 24 | 600 | 1040 | 139.7 | 749 | 610 | 292 | 901.7 | 20 | 2 1/2 | 2 5/8 | 440 |
Class 1500 Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 120 | 22.3 | 38 | 21.3 | 60 | 82.6 | 4 | 3/4 | 7/8 | 110 |
| 3/4 | 20 | 130 | 25.4 | 44 | 26.7 | 70 | 88.9 | 4 | 3/4 | 7/8 | 115 |
| 1 | 25 | 150 | 28.6 | 52 | 33.4 | 73 | 101.6 | 4 | 7/8 | 1 | 125 |
| 1 1/4 | 32 | 160 | 28.6 | 64 | 42.2 | 73 | 111.1 | 4 | 7/8 | 1 | 125 |
| 1 1/2 | 40 | 180 | 31.8 | 70 | 48.3 | 83 | 123.8 | 4 | 1 | 1 1/8 | 140 |
| 2 | 50 | 215 | 38.1 | 105 | 60.3 | 102 | 165.1 | 8 | 7/8 | 1 | 145 |
| 2 1/2 | 65 | 245 | 41.3 | 124 | 73 | 105 | 190.5 | 8 | 1 | 1 1/8 | 160 |
| 3 | 80 | 265 | 47.7 | 133 | 88.9 | 117 | 203.2 | 8 | 1 1/8 | 1 1/4 | 180 |
| 4 | 100 | 310 | 54 | 162 | 114.3 | 124 | 241.3 | 8 | 1 1/4 | 1 3/8 | 195 |
| 5 | 125 | 375 | 73.1 | 197 | 141.3 | 156 | 292.1 | 8 | 1 1/2 | 1 5/8 | 250 |
| 6 | 150 | 395 | 82.6 | 229 | 168.3 | 171 | 317.5 | 12 | 1 3/8 | 1 1/2 | 260 |
| 8 | 200 | 485 | 92.1 | 292 | 219.1 | 213 | 393.7 | 12 | 1 5/8 | 1 3/4 | 290 |
| 10 | 250 | 585 | 108 | 368 | 273 | 254 | 482.6 | 12 | 1 7/8 | 2 | 335 |
| 12 | 300 | 675 | 123.9 | 451 | 323.8 | 283 | 571.5 | 16 | 2 | 2 1/8 | 375 |
| 14 | 350 | 750 | 133.4 | 495 | 355.6 | 298 | 635 | 16 | 2 1/4 | 2 3/8 | 405 |
| 16 | 400 | 825 | 146.1 | 552 | 406.4 | 311 | 704.8 | 16 | 2 1/2 | 2 5/8 | 445 |
| 18 | 450 | 915 | 162 | 597 | 457 | 327 | 774.7 | 16 | 2 3/4 | 2 7/8 | 495 |
| 20 | 500 | 985 | 177.8 | 641 | 508 | 356 | 831.8 | 16 | 3 | 3 1/8 | 540 |
| 24 | 600 | 1170 | 203.2 | 762 | 610 | 406 | 990.6 | 16 | 3 1/2 | 3 5/8 | 615 |
Class 2500 Weld Neck Flange Dimensions
| NPS (in) | DN | OD (mm) | Thickness (mm) | Hub Dia. (mm) | Weld-End OD (mm) | Length Thru Hub (mm) | Bolt Circle (mm) | Bolts | Bolt Size UNC (in) | Bolt Hole (in) | RF Stud (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 15 | 135 | 30.2 | 43 | 21.3 | 73 | 88.9 | 4 | 3/4 | 7/8 | 120 |
| 3/4 | 20 | 140 | 31.8 | 51 | 26.7 | 79 | 95.2 | 4 | 3/4 | 7/8 | 125 |
| 1 | 25 | 160 | 35 | 57 | 33.4 | 89 | 108 | 4 | 7/8 | 1 | 140 |
| 1 1/4 | 32 | 185 | 38.1 | 73 | 42.2 | 95 | 130.2 | 4 | 1 | 1 1/8 | 150 |
| 1 1/2 | 40 | 205 | 44.5 | 79 | 48.3 | 111 | 146 | 4 | 1 1/8 | 1 1/4 | 170 |
| 2 | 50 | 235 | 50.9 | 95 | 60.3 | 127 | 171.4 | 8 | 1 | 1 1/8 | 180 |
| 2 1/2 | 65 | 265 | 57.2 | 114 | 73 | 143 | 196.8 | 8 | 1 1/8 | 1 1/4 | 195 |
| 3 | 80 | 305 | 66.7 | 133 | 88.9 | 168 | 228.6 | 8 | 1 1/4 | 1 3/8 | 220 |
| 4 | 100 | 355 | 76.2 | 165 | 114.3 | 190 | 273 | 8 | 1 1/2 | 1 5/8 | 255 |
| 5 | 125 | 420 | 92.1 | 203 | 141.3 | 229 | 323.8 | 8 | 1 3/4 | 1 7/8 | 300 |
| 6 | 150 | 485 | 108 | 235 | 168.3 | 273 | 368.3 | 8 | 2 | 2 1/8 | 345 |
| 8 | 200 | 550 | 127 | 305 | 219.1 | 318 | 438.2 | 12 | 2 | 2 1/8 | 380 |
| 10 | 250 | 675 | 165.1 | 375 | 273 | 419 | 539.8 | 12 | 2 1/2 | 2 5/8 | 490 |
| 12 | 300 | 760 | 184.2 | 441 | 323.8 | 464 | 619.1 | 12 | 2 3/4 | 2 7/8 | 540 |
For sizes, classes or weights beyond this reference table, use our Flange Weight Calculator.
Applications and Industrial Uses of Carbon Steel Weld Neck Flanges
- Oil and gas pipelines and processing plants
- Refineries and petrochemical units
- Power generation, including high-temperature steam lines
- High-pressure piping and pressure vessel nozzles
- Chemical and process industries
Frequently Asked Questions
A forged flange with a long tapered hub, butt welded to the pipe so flange, weld and pipe form one continuous piece. Built to ASME B16.5 and B16.47.
The taper spreads stress gradually from flange to pipe wall instead of concentrating it at a sharp edge, improving resistance to cracking under cyclic pressure, thermal expansion and vibration.
Solitaire Overseas supplies carbon steel weld neck flanges in Class 150, 300, 400, 600, 900, 1500 and 2500 per ASME B16.5 (NPS 1/2-24); larger sizes per B16.47.
ASTM A105 is the standard grade. ASTM A694 F42 to F70 suits higher-yield pipeline duty. See our Carbon Steel High Pressure Flanges page for the grade comparison.
ASME B16.5 lists A105 ratings to 1,000°F (538°C), but pressure capacity drops sharply and graphitization risk rises above about 800°F (427°C). Check the P-T table.
Choose weld neck for high-pressure, cyclic or critical service. Choose slip-on for lower-pressure, cost-sensitive lines, as it costs less and aligns easily but has lower fatigue strength.
A one-piece, straight-bore nozzle flange with an extended hub, used on pressure vessels and tanks in place of a weld neck flange welded to a pipe stub.
Contact Solitaire Overseas for expert guidance and the right flange solution for your application.
Carbon Steel Flanges, Carbon Steel Pipe Flanges, Carbon Steel High Pressure Flanges, and Carbon Steel Forged Flanges.