Weld Neck Flange

  • Size Range: DN15-DN600 (1/2″ to 24″)
  • Pressure Class: PN20-PN420 (Class 150 to Class 2500)
  • Flange Facing: RF (Raised Face), RJ (Ring Joint), M (Male Face), FM (Female Face), T (Tongue), G (Groove)
  • Manufacturing Standards: ASME B16.5, JIS B2220, EN 1092-1, HG/T 20592 and other international standards
  • Body Material Options: 304 / 316L Stainless Steel, Hastelloy C, Alloy 20, Duplex 2205, Super Duplex 2507, 904L, 310S, Titanium TA2, Carbon Steel 20# and customized materials
  • Temperature Range: -196°C to +1000°C
  • Compatible Media: Water, neutral gas, liquids, alcohol, oil, fuel, steam, organic solvents, acidic and alkaline media
  • Industries Served: Oil & Gas, Petrochemical, Chemical, Power, Marine, Food & Beverage, Pharmaceutical, Water Treatment, HVAC, Metallurgy, and Environmental Engineering.

Product details

Weld Neck Flange, commonly known as WN Flange, is a high-performance forged flange designed for high-pressure and high-temperature piping systems.

The term “Weld Neck” refers to the flange’s long tapered hub with increased wall thickness, while “Butt Weld” indicates the connection method where the beveled end of the flange neck is aligned with the pipe and joined by full penetration welding.

As one of the strongest and most reliable flange types used in pressure piping systems, the Weld Neck Flange provides excellent sealing performance, superior mechanical strength, and outstanding resistance to pressure and temperature stresses.

The connection area between the flange body and pipeline adopts a gradually tapered reinforced hub design, allowing stress to be evenly distributed and reducing stress concentration. This structure effectively prevents stress cracking and enables the flange to withstand.

The flange neck is machined with a standard welding bevel, allowing full penetration butt welding with seamless pipes. The weld strength is equivalent to the parent pipe material, ensuring excellent overall pressure-bearing capability and structural integrity.

Product Specifications

Note: The flange inner diameter (B) is determined by the wall thickness of the steel pipe and shall be specified by the user at the time of ordering.(Unit: mm)

WN-150LB-2500LB

DNNPSType/ClassPart NoADKLThnCNHd1fPEFdwXyZ
15 0.5WN-150LB-SFTXLXWN150SFT0521.3 90.0 60.3 16.0 M144.0 9.6 15.5 46.0 35.1 1.5
20 0.75WN-150LB-SFTXLXWN150SFT07526.9 100.0 69.9 16.0 M144.0 11.2 21.0 51.0 42.9 1.5
25 1WN-150LB-SFTXLXWN150SFT133.7 110.0 79.4 16.0 M144.0 12.7 27.0 54.0 50.8 1.5 47.6 6.4 8.7
32 1.25WN-150LB-SFTXLXWN150SFT12542.4 115.0 88.9 16.0 M144.0 14.3 35.0 56.0 63.5 1.5 57.2 6.4 8.7
40 1.5WN-150LB-SFTXLXWN150SFT1548.3 125.0 98.4 16.0 M144.0 15.9 41.0 60.0 73.0 1.5 65.1 6.4 8.7
50 2WN-150LB-SFTXLXWN150SFT260.3 150.0 120.7 18.0 M164.0 17.5 52.0 62.0 91.9 1.5 82.6 6.4 8.7
65 2.5WN-150LB-SFTXLXWN150SFT2576.1 180.0 139.7 18.0 M164.0 20.7 66.0 68.0 104.6 1.5 101.6 6.4 8.7
80 3WN-150LB-SFTXLXWN150SFT388.9 190.0 152.4 18.0 M164.0 22.3 77.5 68.0 127.0 1.5 114.3 6.4 8.7
100 4WN-150LB-SFTXLXWN150SFT4114.3 230.0 190.5 18.0 M168.0 22.3 101.5 75.0 157.2 1.5 149.2 6.4 8.7
125 5WN-150LB-SFTXLXWN150SFT5139.7 255.0 215.9 22.0 M208.0 22.3 127.0 87.0 185.7 1.5 171.5 6.4 8.7
150 6WN-150LB-SFTXLXWN150SFT6168.3 280.0 241.3 22.0 M208.0 23.9 154.0 87.0 215.9 1.5 193.7 6.4 8.7
200 8WN-150LB-SFTXLXWN150SFT8219.1 345.0 298.5 22.0 M208.0 27.0 203.0 100.0 269.7 1.5 247.7 6.4 8.7
250 10WN-150LB-SFTXLXWN150SFT10273.0 405.0 362.0 26.0 M2412.0 28.6 255.0 100.0 323.8 1.5 304.8 6.4 8.7
300 12WN-150LB-SFTXLXWN150SFT12323.9 485.0 431.8 26.0 M2412.0 30.2 303.5 113.0 381.0 1.5 381.0 6.4 8.7
350 14WN-150LB-SFTXLXWN150SFT14355.6 535.0 476.3 30.0 M2712.0 33.4 125.0 412.8 1.5 396.9 6.4 8.7
400 16WN-150LB-SFTXLXWN150SFT16406.4 595.0 539.8 30.0 M2716.0 35.0 125.0 469.9 1.5 454.0 6.4 8.7
450 18WN-150LB-SFTXLXWN150SFT18457.0 635.0 577.9 33.0 M3016.0 38.1 138.0 533.4 1.5 517.5 6.4 8.7
500 20WN-150LB-SFTXLXWN150SFT20508.0 700.0 635.0 33.0 M3020.0 41.3 143.0 584.2 1.5 558.8 6.4 8.7
600 24WN-150LB-SFTXLXWN150SFT24610.0 815.0 749.3 36.0 M3320.0 46.1 151.0 692.2 1.5 673.1 6.4 8.7
15 0.5WN-300LB-SFTXLXWN300SFT0521.3 95 66.7 16 M144 12.7 38 51 35 2 34.1 5.5 7.1 46.0 25.4 34.9 36.5 23.8
20 0.75WN-300LB-SFTXLXWN300SFT07526.9 115 82.6 18 M164 14.3 48 56 43 2 42.9 6.4 8.7 54.0 33.3 42.9 44.4 31.8
25 1WN-300LB-SFTXLXWN300SFT133.7 125 88.9 18 M164 15.9 54 60 51 2 50.8 6.4 8.7 62.0 38.1 50.8 52.4 36.5
32 1.25WN-300LB-SFTXLXWN300SFT12542.4 135 98.4 18 M164 17.5 64 64 64 2 60.3 6.4 8.7 75.0 47.6 63.5 65.1 46.0
40 1.5WN-300LB-SFTXLXWN300SFT1548.3 155 114.3 22 M204 19.1 70 67 73 2 68.3 6.4 8.7 84.0 54.0 73.0 74.6 52.4
50 2WN-300LB-SFTXLXWN300SFT260.3 165 127.0 18 M168 20.7 84 68 92 2 82.6 7.9 11.9 103.0 73.0 92.1 93.7 71.4
65 2.5WN-300LB-SFTXLXWN300SFT2576.1 190 149.2 22 M208 23.9 100 75 105 2 101.6 7.9 11.9 116.0 85.7 104.8 106.4 84.1
80 3WN-300LB-SFTXLXWN300SFT388.9 210 168.3 22 M208 27.0 117 78 127 2 123.8 7.9 11.9 138.0 108.0 127.0 128.6 106.4
100 4WN-300LB-SFTXLXWN300SFT4114.3 255 200.0 22 M208 30.2 146 84 157 2 149.2 7.9 11.9 168.0 131.8 157.2 158.8 130.2
125 5WN-300LB-SFTXLXWN300SFT5139.7 280 235.0 22 M208 33.4 178 97 186 2 181.0 7.9 11.9 197.0 160.3 185.7 187.3 158.8
150 6WN-300LB-SFTXLXWN300SFT6168.3 320 269.9 22 M2012 35.0 206 97 216 2 211.1 7.9 11.9 227.0 190.5 215.9 217.5 188.9
200 8WN-300LB-SFTXLXWN300SFT8219.1 380 330.2 26 M2412 39.7 260 110 270 2 269.9 7.9 11.9 281.0 238.1 269.9 271.5 236.5
250 10WN-300LB-SFTXLXWN300SFT10273 445 387.4 30 M2716 46.1 321 116 324 2 323.9 7.9 11.9 335.0 285.8 323.8 325.4 284.2
300 12WN-300LB-SFTXLXWN300SFT12323.9 520 450.8 33 M3016 49.3 375 129 381 2 381.0 7.9 11.9 392.0 342.9 381.0 382.6 341.3
350 14WN-300LB-SFTXLXWN300SFT14355.6 585 514.4 33 M3020 52.4 425 141 413 2 419.1 7.9 11.9 424.0 374.6 412.8 414.3 373.1
400 16WN-300LB-SFTXLXWN300SFT16406.4 650 571.5 36 M3320 55.6 483 144 470 2 469.9 7.9 11.9 481.0 425.4 469.9 471.5 423..9
450 18WN-300LB-SFTXLXWN300SFT18457 710 628.6 36 M3324 58.8 533 157 533 2 533.4 7.9 11.9 544.0 489.0 533.4 535.0 487.4
500 20WN-300LB-SFTXLXWN300SFT20508 775 685.8 36 M3324 62.0 587 160 584 2 584.2 9.5 13.5 595.0 533.4 584.2 585.8 531.8
600 24WN-300LB-SFTXLXWN300SFT24610 915 812.8 42 M39×324 68.3 702 167 692 2 692.2 11.1 16.7 703.0 641.4 692.2 693.7 639.8
15 0.5WN-600LB-SFTXLXWN600SFT0521.3 95 66.7 16 M144 14.3 38 52 35.1 6.4 34.1 5.5 7.1 46.0 25.4 34.9 36.5 23.8
20 0.75WN-600LB-SFTXLXWN600SFT07526.9 115 82.6 18 M164 15.9 48 57 42.9 6.4 42.9 6.4 8.7 54.0 33.3 42.9 44.4 31.8
25 1WN-600LB-SFTXLXWN600SFT133.7 125 88.9 18 M164 17.5 54 62 50.8 6.4 50.8 6.4 8.7 62.0 38.1 50.8 52.4 36.5
32 1.25WN-600LB-SFTXLXWN600SFT12542.4 135 98.4 18 M164 20.7 64 67 63.5 6.4 60.3 6.4 8.7 75.0 47.6 63.5 65.1 46.0
40 1.5WN-600LB-SFTXLXWN600SFT1548.3 155 114.3 22 M204 22.3 70 70 73.0 6.4 68.3 6.4 8.7 84.0 54.0 73.0 74.6 52.4
50 2WN-600LB-SFTXLXWN600SFT260.3 165 127.0 18 M168 25.4 84 73 91.9 6.4 82.6 7.9 11.9 103.0 73.0 92.1 93.7 71.4
65 2.5WN-600LB-SFTXLXWN600SFT2576.1 190 149.2 22 M208 28.6 100 79 104.6 6.4 101.6 7.9 11.9 116.0 85.7 104.8 106.4 84.1
80 3WN-600LB-SFTXLXWN600SFT388.9 210 168.3 22 M208 31.8 117 83 127.0 6.4 123.8 7.9 11.9 138.0 108.0 127.0 128.6 106.4
100 4WN-600LB-SFTXLXWN600SFT4114.3 275 215.9 26 M248 38.1 152 102 157.2 6.4 149.2 7.9 11.9 168.0 131.8 157.2 158.8 130.2
125 5WN-600LB-SFTXLXWN600SFT5140 330 267 30 M278 45 189 114 185.7 6.4 181.0 7.9 11.9 197.0 160.3 185.7 187.3 158.8
150 6WN-600LB-SFTXLXWN600SFT6168 355 292 30 M2712 48 222 117 215.9 6.4 211.1 7.9 11.9 227.0 190.5 215.9 217.5 188.9
200 8WN-600LB-SFTXLXWN600SFT8219 420 349 33 M3012 56 273 133 269.7 6.4 269.9 7.9 11.9 281.0 238.1 269.9 271.5 236.5
250 10WN-600LB-SFTXLXWN600SFT10273 510 432 36 M3316 64 343 152 323.8 6.4 323.9 7.9 11.9 335.0 285.8 323.8 325.4 284.2
300 12WN-600LB-SFTXLXWN600SFT12324 560 489 36 M3320 67 400 156 381.0 6.4 381.0 7.9 11.9 392.0 342.9 381.0 382.6 341.3
350 14WN-600LB-SFTXLXWN600SFT14356 605 527 39 M36×320 70 432 165 412.8 6.4 419.1 7.9 11.9 424.0 374.6 412.8 414.3 373.1
400 16WN-600LB-SFTXLXWN600SFT16406 685 603 42 M39×320 76 495 178 469.9 6.4 469.9 7.9 11.9 481.0 425.4 469.9 471.5 423..9
450 18WN-600LB-SFTXLXWN600SFT18457 745 654 45 M42×320 83 546 184 533.4 6.4 533.4 7.9 11.9 544.0 489.0 533.4 535.0 487.4
500 20WN-600LB-SFTXLXWN600SFT20508 815 724 45 M42×324 89 610 190 584.2 6.4 584.2 9.5 13.5 595.0 533.4 584.2 585.8 531.8
600 24WN-600LB-SFTXLXWN600SFT24640 940 838 51 M48×324 102 718 203 692.2 6.4 692.2 11.1 16.7 703.0 641.4 692.2 693.7 639.8
15 0.5WN-900LB-SFTXLXWN900SFT0521.3 120 82.6 22 M204 22.3 38 60 35.1 6.4 39.676.358.744625.434.936.523.8
20 0.75WN-900LB-SFTXLXWN900SFT07526.9 130 88.9 22 M204 25.4 44 70 42.9 6.4 44.456.358.745433.342.944.431.8
25 1WN-900LB-SFTXLXWN900SFT133.7 150 101.6 26 M244 28.6 52 73 50.8 6.4 50.86.358.746238.150.852.436.5
32 1.25WN-900LB-SFTXLXWN900SFT12542.4 160 111.1 26 M244 28.6 64 73 63.5 6.4 60.336.358.747547.663.565.146
40 1.5WN-900LB-SFTXLXWN900SFT1548.3 180 123.8 30 M274 31.8 70 83 73.0 6.4 68.276.358.7484547374.652.4
50 2WN-900LB-SFTXLXWN900SFT260.3 215 165.1 26 M248 38.1 105 102 91.9 6.4 95.257.9211.911037392.193.771.4
65 2.5WN-900LB-SFTXLXWN900SFT2576.1 245 190.5 30 M278 41.3 124 105 104.6 6.4 107.957.9211.9111685.7104.8106.484.1
80 3WN-900LB-SFTXLXWN900SFT388.9 240 190.5 26 M248 38.1 127 102 127.0 6.4 123.837.9211.91138108127128.6106.4
100 4WN-900LB-SFTXLXWN900SFT4114.3 290 235.0 33 M308 44.5 159 114 157.2 6.4 149.237.9211.91168131.8157.2158.8130.2
125 5WN-900LB-SFTXLXWN900SFT5139.7 350 279.4 36 M338 50.8 190 127 185.7 6.4 180.987.9211.91197160.3185.7187.3158.8
150 6WN-900LB-SFTXLXWN900SFT6168.3 380 317.5 33 M3012 55.6 235 140 215.9 6.4 211.127.9211.91227190.5215.9217.5188.9
200 8WN-900LB-SFTXLXWN900SFT8219.1 470 393.7 39 M36×312 63.5 298 162 269.7 6.4 269.887.9211.91281238.1269.9271.5236.5
250 10WN-900LB-SFTXLXWN900SFT10273 545 469.9 39 M36×316 69.9 368 184 323.8 6.4 323.857.9211.91335285.8323.8325.4284.2
300 12WN-900LB-SFTXLXWN900SFT12323.9 610 533.4 39 M36×320 79.4 419 200 381.0 6.4 3817.9211.91392342.9381382.6341.3
350 14WN-900LB-SFTXLXWN900SFT14355.6 640 558.8 42 M39×320 85.8 451 213 412.8 6.4 419.111.1316.66424374.6412.8414.3373.1
400 16WN-900LB-SFTXLXWN900SFT16406.4 705 616.0 45 M42×320 88.9 508 216 469.9 6.4 469.911.1316.66481425.4469.9471.5423..9
450 18WN-900LB-SFTXLXWN900SFT18457 785 685.8 51 M48×320 101.6 565 229 533.4 6.4 533.412.719.84544489533.4535487.4
500 20WN-900LB-SFTXLXWN900SFT20508 855 749.3 55 M52×320 108.0 622 248 584.2 6.4 584.212.719.84595533.4584.2585.8531.8
600 24WN-900LB-SFTXLXWN900SFT24610 1040 901.7 68 M64×320 139.7 749 292 692.2 6.4 692.1515.8826.97703641.4692.2693.7639.8
15 0.5WN-1500LB-SFTXLXWN1500SFT0521.3 120 82.6 22 M204 22.3 38 60 35.1 6.4 39.676.358.744625.434.936.523.8
20 0.75WN-1500LB-SFTXLXWN1500SFT07526.9 130 88.9 22 M204 25.4 44 70 42.9 6.4 44.456.358.745433.342.944.431.8
25 1WN-1500LB-SFTXLXWN1500SFT133.7 150 101.6 26 M244 28.6 52 73 50.8 6.4 50.86.358.746238.150.852.436.5
32 1.25WN-1500LB-SFTXLXWN1500SFT12542.4 160 111.1 26 M244 28.6 64 73 63.5 6.4 60.336.358.747547.663.565.146
40 1.5WN-1500LB-SFTXLXWN1500SFT1548.3 180 123.8 30 M274 31.8 70 83 73.0 6.4 68.276.358.7484547374.652.4
50 2WN-1500LB-SFTXLXWN1500SFT260.3 215 165.1 26 M248 38.1 105 102 91.9 6.4 95.257.9211.911037392.193.771.4
65 2.5WN-1500LB-SFTXLXWN1500SFT2576.1 245 190.5 30 M278 41.3 124 105 104.6 6.4 107.957.9211.9111685.7104.8106.484.1
80 3WN-1500LB-SFTXLXWN1500SFT388.9 265 203.2 33 M308 47.7 133 117 127.0 6.4 136.537.9211.91138108127128.6106.4
100 4WN-1500LB-SFTXLXWN1500SFT4114.3 310 241.3 36 M338 54.0 162 124 157.2 6.4 161.937.9211.91168131.8157.2158.8130.2
125 5WN-1500LB-SFTXLXWN1500SFT5139.7 375 292.1 42 M39×38 73.1 197 156 185.7 6.4 193.687.9211.91197160.3185.7187.3158.8
150 6WN-1500LB-SFTXLXWN1500SFT6168.3 395 317.5 39 M36×312 82.6 229 171 215.9 6.4 211.149.5313.49227190.5215.9217.5188.9
200 8WN-1500LB-SFTXLXWN1500SFT8219.1 485 393.7 45 M42×312 92.1 292 213 269.7 6.4 269.8811.1316.66281238.1269.9271.5236.5
250 10WN-1500LB-SFTXLXWN1500SFT10273 585 482.6 51 M48×312 108.0 368 254 323.8 6.4 323.8511.1316.66335285.8323.8325.4284.2
300 12WN-1500LB-SFTXLXWN1500SFT12323.9 675 571.5 55 M52×316 123.9 451 283 381.0 6.4 38114.2723.01392342.9381382.6341.3
350 14WN-1500LB-SFTXLXWN1500SFT14355.6 750 635.0 60 M56×316 133.4 495 298 412.8 6.4 419.115.8826.97424374.6412.8414.3373.1
400 16WN-1500LB-SFTXLXWN1500SFT16406.4 825 704.8 68 M64×316 146.1 552 311 469.9 6.4 469.917.4830.18481425.4469.9471.5423..9
450 18WN-1500LB-SFTXLXWN1500SFT18457 915 774.7 74 M70×316 162.0 597 327 533.4 6.4 533.417.4830.18544489533.4535487.4
500 20WN-1500LB-SFTXLXWN1500SFT20508 985 831.8 80 M76×316 177.8 641 356 584.2 6.4 584.217.4833.32595533.4584.2585.8531.8
600 24WN-1500LB-SFTXLXWN1500SFT24610 1170 990.6 94 M90×316 203.2 762 406 692.2 6.4 692.1520.6236.53703641.4692.2693.7639.8
15 0.5WN-2500LB-SFTXLXWN2500SFT0521.3 135 88.9 22 M204 30.2 43 73 35.1 6.4 42.886.358.744625.434.936.523.8
20 0.75WN-2500LB-SFTXLXWN2500SFT07526.9 140 95.2 22 M204 31.8 51 79 42.9 6.4 50.86.358.745433.342.944.431.8
25 1WN-2500LB-SFTXLXWN2500SFT133.7 160 108.0 26 M244 35.0 57 89 50.8 6.4 60.336.358.746238.150.852.436.5
32 1.25WN-2500LB-SFTXLXWN2500SFT12542.4 185 130.2 30 M274 38.1 73 95 63.5 6.4 72.237.9211.917547.663.565.146
40 1.5WN-2500LB-SFTXLXWN2500SFT1548.3 205 146.0 33 M304 44.5 79 111 73.0 6.4 82.557.9211.9184547374.652.4
50 2WN-2500LB-SFTXLXWN2500SFT260.3 235 171.4 30 M278 50.9 95 127 91.9 6.4 101.67.9211.911037392.193.771.4
65 2.5WN-2500LB-SFTXLXWN2500SFT2576.1 265 196.8 33 M308 57.2 114 143 104.6 6.4 111.139.5213.4911685.7104.8106.484.1
80 3WN-2500LB-SFTXLXWN2500SFT388.9 305 228.6 36 M338 66.7 133 168 127.0 6.4 1279.5313.49138108127128.6106.4
100 4WN-2500LB-SFTXLXWN2500SFT4114.3 355 273.0 42 M39×38 76.2 165 190 157.2 6.4 157.1811.1316.66168131.8157.2158.8130.2
125 5WN-2500LB-SFTXLXWN2500SFT5139.7 420 323.8 48 M45×38 92.1 203 229 185.7 6.4 190.512.719.84197160.3185.7187.3158.8
150 6WN-2500LB-SFTXLXWN2500SFT6168.3 485 368.3 55 M52×38 108.0 235 273 215.9 6.4 228.612.719.84227190.5215.9217.5188.9
200 8WN-2500LB-SFTXLXWN2500SFT8219.1 550 438.2 55 M52×312 127.0 305 318 269.7 6.4 279.414.2723.01281238.1269.9271.5236.5
250 10WN-2500LB-SFTXLXWN2500SFT10273 675 539.8 68 M64×312 165.1 375 419 323.8 6.4 342.917.4830.18335285.8323.8325.4284.2
300 12WN-2500LB-SFTXLXWN2500SFT12323.9 760 619.1 74 M70×312 184.2 441 464 381.0 6.4 406.417.4833.32392342.9381382.6341.3

RF (Raised Face): The most widely used facing type for general applications. Suitable for steam systems, water supply and drainage pipelines, and conventional chemical processing lines.

MFM (Male & Female Face): Designed to improve sealing reliability by preventing gasket extrusion under higher pressure conditions. Suitable for applications involving higher medium pressure and demanding sealing requirements.

RJ (Ring Type Joint Face): Designed for ultra-high pressure and critical service applications, such as oil & gas pipelines and high-pressure main piping systems in power plants. Combined with metallic ring gaskets, it provides excellent sealing performance and zero leakage reliability.

Manufactured by integral forging process to ensure high density and uniform mechanical properties.

Eliminates defects commonly found in cast products, such as porosity, shrinkage cavities, and internal looseness.

Provides superior strength, durability, and pressure resistance.

Manufactured in accordance with pressure equipment and pressure piping standards.