Kwality Steel (India)
HomeWeldneck Flanges

Weldneck Flanges

Certified steel products, dependable supply and application-focused support for industrial buyers.

Weldneck Flanges

Weldneck flanges provide high-strength welded joints for severe service, thermal cycling and high-pressure piping. Their tapered hub transfers stress smoothly from flange to pipe, making them suitable for refineries, chemical plants, power plants and critical equipment connections. We supply weldneck flanges with correct bore, face finish and certified material documentation.

Size Range1/2 inch to 48 inch
Wall / Pressure ClassClass 150 to 2500
TypesStandard Bore, Heavy Bore, Long Weld Neck
StandardsASME B16.5, ASME B16.47
FinishRF, RTJ, Smooth, Serrated
LengthStandard/long neck

Materials Grades

Available in corrosion-resistant, high-temperature and pressure-grade materials for industrial service. Grade selection can be aligned with pressure, temperature, corrosion allowance and client specification.

Stainless Steel 304/304LStainless Steel 316/316LCarbon SteelAlloy SteelDuplex 2205Super Duplex 2507InconelMonelHastelloyTitanium

Dimensions Chart

Hub and bore dimensions depend on schedule; table lists standard drilling and reference bore.

ASME B16.5 Slip On Flange Drawing

Class 150 Weld Neck Flange Dimensions

NPS Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Hub Outer Diameter Weld Neck Outer Diameter Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 90 9.6 30 21.3 46 - 34.9 2 60.3 1.6
3/4 20 100 11.2 38 26.7 51 42.9 2 69.9 1.6
1 25 110 12.7 49 33.4 54 50.8 2 79.4 1.6
1 1/4 32 115 14.3 59 42.2 56 63.5 2 88.9 1.6
1 1/2 40 125 15.9 65 48.3 60 73 2 98.4 1.6
2 50 150 17.5 78 60.3 62 92.1 2 120.7 1.6
2 1/2 65 180 20.7 90 73 68 104.8 2 139.7 1.6
3 80 190 22.3 108 88.9 68 127 2 152.4 1.6
3 1/2 90 215 22.3 122 101.6 70 139.7 2 177.8 1.6
4 100 230 22.3 135 114.3 75 157.2 2 190.5 1.6
5 125 255 22.3 164 141.3 87 185.7 2 215.9 1.6
6 150 280 23.9 192 168.3 87 215.9 2 241.3 1.6
8 200 345 27 246 219.1 100 269.9 2 298.5 1.6
10 250 405 28.6 305 273 100 323.8 2 362 1.6
12 300 485 30.2 365 323.8 113 381 2 431.8 1.6
14 350 535 33.4 400 355.6 125 412.8 2 476.3 1.6
16 400 595 35 457 406.4 125 469.9 2 539.8 1.6
18 450 635 38.1 505 457.2 138 533.4 2 577.9 1.6
20 500 700 41.3 559 508 143 584.2 2 635 1.6
24 600 815 46.1 663 610 151 692.2 2 749.3 1.6

Class 300 Weld Neck Flange Dimensions

NPS Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Outside Daimeter Of Hub Outside Daimeter Of Weld Neck Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 95 12.7 38 21.3 51 Refer Note 34.9 2 66.7 1.6
3/4 20 115 14.3 48 26.7 56 42.9 2 82.6 1.6
1 25 125 15.9 54 33.4 60 50.8 2 88.9 1.6
1 1/4 32 135 17.5 64 42.2 64 63.5 2 98.4 1.6
1 1/2 40 155 19.1 70 48.3 67 73 2 114.3 1.6
2 50 165 20.7 84 60.3 68 92.1 2 127 1.6
2 1/2 65 190 23.9 100 73 75 104.8 2 149.2 1.6
3 80 210 27 117 88.9 78 127 2 168.3 1.6
3 1/2 90 230 28.6 133 101.6 79 139.7 2 184.2 1.6
4 100 255 30.2 146 114.3 84 157.2 2 200 1.6
5 125 280 33.4 178 141.3 97 185.7 2 235 1.6
6 150 320 35 206 168.3 97 215.9 2 269.9 1.6
8 200 380 39.7 260 219.1 110 269.9 2 330.2 1.6
10 250 445 46.1 321 273 116 323.8 2 387.4 1.6
12 300 520 49.3 375 323.8 129 381 2 450.8 1.6
14 350 585 52.4 425 355.6 141 412.8 2 514.4 1.6
16 400 650 55.6 483 406.4 144 469.9 2 571.5 1.6
18 450 710 58.8 533 457 157 533.4 2 628.6 1.6
20 500 775 62 587 508 160 584.2 2 685.8 1.6
24 600 915 68.3 702 610 167 692.2 2 812.8 1.6

Class 400 Weld Neck Flange Dimensions

NPS Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Outside Daimeter Of Hub Outside Daimeter Of Weld Neck Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 95 14.3 38 21.3 52 - 34.9 7 66.7 1.6
3/4 20 115 15.9 48 26.7 57 42.9 7 82.6 1.6
1 25 125 17.5 54 33.4 62 50.8 7 88.9 1.6
1 1/4 32 135 20.7 64 42.2 67 63.5 7 98.4 1.6
1 1/2 40 155 22.3 70 48.3 70 73 7 114.3 1.6
2 50 165 25.4 84 60.3 73 92.1 7 127 1.6
2 1/2 65 190 28.6 100 73 79 104.8 7 149.2 1.6
3 80 210 31.8 117 88.9 83 127 7 168.3 1.6
3 1/2 90 230 35 133 101.6 86 139.7 7 184.2 1.6
4 100 255 35 146 114.3 89 157.2 7 200 1.6
5 125 280 38.1 178 141.3 102 185.7 7 235 1.6
6 150 320 41.3 206 168.3 103 215.9 7 269.9 1.6
8 200 380 47.7 260 219.1 117 269.9 7 330 1.6
10 250 445 54 321 273 124 323.8 7 387.4 1.6
12 300 520 57.2 375 323.8 137 381 7 450.8 1.6
14 350 585 60.4 425 355.6 149 412.8 7 514.4 1.6
16 400 650 63.5 483 406.4 152 469.9 7 571.5 1.6
18 450 710 66.7 533 457 165 533.4 7 628.6 1.6
20 500 775 69.9 587 508 168 584.2 7 685.8 1.6
24 600 915 76.2 702 610 175 692.2 7 812.8 1.6

Class 600 Weld Neck Flange Dimensions

NPS Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Outside Daimeter Of Hub Outside Daimeter Of Weld Neck Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 95 14.3 38 21.3 52 - 34.9 7 66.7 1.6
3/4 20 115 15.9 48 26.7 57 42.9 7 82.6 1.6
1 25 125 17.5 54 33.4 62 50.8 7 88.9 1.6
1 1/4 32 135 20.7 64 42.2 67 63.5 7 98.4 1.6
1 1/2 40 155 22.3 70 48.3 70 73 7 114.3 1.6
2 50 165 25.4 84 60.3 73 92.1 7 127 1.6
2 1/2 65 190 28.6 100 73 79 104.8 7 149.2 1.6
3 80 210 31.8 117 88.9 83 127 7 168.3 1.6
3 1/2 90 230 35 133 101.6 86 139.7 7 184.2 1.6
4 100 275 38.1 152 114.3 102 157.2 7 215.9 1.6
5 125 330 44.5 189 141.3 114 185.7 7 266.7 1.6
6 150 355 47.7 222 168.3 117 215.9 7 292.1 1.6
8 200 420 55.6 273 219.1 133 269.9 7 349.2 1.6
10 250 510 63.5 343 273 152 323.8 7 431.8 1.6
12 300 560 66.7 400 323.8 156 381 7 489 1.6
14 350 605 69.9 432 355.6 165 412.8 7 527 1.6
16 400 685 76.2 495 406.4 178 469.9 7 603.2 1.6
18 450 745 82.6 546 457 184 533.4 7 654 1.6
20 500 815 88.9 610 508 190 584.2 7 723.9 1.6
24 600 940 101.6 718 610 203 692.2 7 838.2 1.6

Class 900 Weld Neck Flange Dimensions

NPS Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Outside Daimeter Of Hub Outside Daimeter Of Weld Neck Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 120 22.3 38 21.3 60 Refer Note 34.9 7 82.6 1.6
3/4 20 130 25.4 44 26.7 70 42.9 7 88.9 1.6
1 25 150 28.6 52 33.4 73 50.8 7 101.6 1.6
1 1/4 32 160 28.6 64 42.2 73 63.5 7 111.1 1.6
1 1/2 40 180 31.8 70 48.3 83 73 7 123.8 1.6
2 50 215 38.1 105 60.3 102 92.1 7 165.1 1.6
2 1/2 65 245 41.3 124 73 105 104.8 7 190.5 1.6
3 80 240 38.1 127 88.9 102 127 7 190.5 1.6
4 100 290 44.5 159 114.3 114 157.2 7 235 1.6
5 125 350 50.8 190 141.3 127 185.7 7 279.4 1.6
6 150 380 55.6 235 168.3 140 215.9 7 317.5 1.6
8 200 470 63.5 298 219.1 162 269.9 7 393.7 1.6
10 250 545 69.9 368 273 184 323.8 7 469.9 1.6
12 300 610 79.4 419 323.8 200 381 7 533.4 1.6
14 350 640 85.8 451 355.6 213 412.8 7 558.8 1.6
16 400 705 88.9 508 406.4 216 469.9 7 616 1.6
18 450 785 101.6 565 457 229 533.4 7 685.8 1.6
20 500 855 108 622 508 248 584.2 7 749.3 1.6
24 600 1040 139.7 749 610 292 692.2 7 901.7 1.6

Class 1500 Weld Neck Flange Dimensions

Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Outside Daimeter Of Hub Outside Daimeter Of Weld Neck Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 120 22.3 38 21.3 60 - 34.9 7 82.6 1.6
3/4 20 130 25.4 44 26.7 70 42.9 7 88.9 1.6
1 25 150 28.6 52 33.4 73 50.8 7 101.6 1.6
1 1/4 32 160 28.6 64 42.2 73 63.5 7 111.1 1.6
1 1/2 40 180 31.8 70 48.3 83 73 7 123.8 1.6
2 50 215 38.1 105 60.3 102 92.1 7 165.1 1.6
2 1/2 65 245 41.3 124 73 105 104.8 7 190.5 1.6
3 80 265 47.7 133 88.9 117 127 7 203.2 1.6
4 100 310 54 162 114.3 124 157.2 7 241.3 1.6
5 125 375 73.1 197 141.3 156 185.7 7 292.1 1.6
6 150 395 82.6 229 168.3 171 215.9 7 317.5 1.6
8 200 485 92.1 292 219.1 213 269.9 7 393.7 1.6
10 250 585 108 368 273 254 323.8 7 482.6 1.6
12 300 675 123.9 451 323.8 283 381 7 571.5 1.6
14 350 750 133.4 495 355.6 298 412.8 7 635 1.6
16 400 825 146.1 552 406.4 311 469.9 7 704.8 1.6
18 450 915 162 597 457 327 533.4 7 774.7 1.6
20 500 985 177.8 641 508 356 584.2 7 831.8 1.6
24 600 1170 203.2 762 610 406 692.2 7 990.6 1.6

Class 2500 Weld Neck Flange Dimensions

Size in Inch NPS Size in mm (O.D.) Outer Diameter Thickness Of Flange Outside Daimeter Of Hub Outside Daimeter Of Weld Neck Length Of Welding Neck Bore Diameter Of RF Height Of RF PCD Weld Face
A B C D E F G H I J
1/2 15 135 30.2 43 21.3 73 - 34.9 7 88.9 1.6
3/4 20 140 31.8 51 26.7 79 42.9 7 95.2 1.6
1 25 160 35 57 33.4 89 50.8 7 108 1.6
1 1/4 32 185 38.1 73 42.2 95 63.5 7 130.2 1.6
1 1/2 40 205 44.5 79 48.3 111 73 7 146 1.6
2 50 235 50.9 95 60.3 127 92.1 7 171.4 1.6
2 1/2 65 265 57.2 114 73 143 104.8 7 196.8 1.6
3 80 305 66.7 133 88.9 168 127 7 228.6 1.6
4 100 355 76.2 165 114.3 190 157.2 7 273 1.6
5 125 420 92.1 203 141.3 229 185.7 7 323.8 1.6
6 150 485 108 235 168.3 273 215.9 7 368.3 1.6
8 200 550 127 305 219.1 318 269.9 7 438.2 1.6
10 250 675 165.1 375 273 419 323.8 7 539.8 1.6
12 300 760 184.2 441 323.8 464 381 7 619.1 1.6

Applications

Oil & Gas

Reliable performance for demanding fabrication, maintenance and process piping needs.

Petrochemical

Reliable performance for demanding fabrication, maintenance and process piping needs.

Power & Energy

Reliable performance for demanding fabrication, maintenance and process piping needs.

Marine

Reliable performance for demanding fabrication, maintenance and process piping needs.

Chemical

Reliable performance for demanding fabrication, maintenance and process piping needs.

Construction

Reliable performance for demanding fabrication, maintenance and process piping needs.

Kwality Steel (India)