API 6 A6BX and 6B Flanges
Api 6A 6BX and API 6A 6B Flanges (welding neck flanges, blind flanges, target flanges and test flanges) are fully conformed to API 6A and made of modern alloy steel via advanced manufacturing techniques. They are robust and high cost performance.
API 6 A 6B flanges are of the ring joint type and are not designed for face-to-face make-up. The connection make-up bolting force reacts on the metallic ring gasket
API 6A 6BX flanges are of the ring joint type and designed with a raised face. Depending on the tolerances, the connection make-up bolting force may react on the raised face of the flange when the gasket has been properly seated. This support prevents damage to the flange or gasket from excessive bolt torque.
API 6A 6BX Welding Neck Flanges
API 6A Type 6BX 15000PSI Blind / API 6A Welding Neck Flange
Dimension of 15000PSI(103.5MPA) type 6BX Blind and API 6A Welding Neck Flange
| Size | B | OD | C | E1 | Q | G | K | T | J1 | J2 | J3 | J4 | R | BC | N | H | Ring Number |
| 1 13/16″ | 46.8 | 210 | 3 | – | 5.56 | 77.77 | 106 | 45.3 | 97.6 | 71.4 | 47.6 | – | 10 | 160.3 | 8 | 26 | 151 |
| 2 1/16″ | 53.2 | 220 | 3 | – | 5.95 | 86.23 | 114 | 50.8 | 111.1 | 82.5 | 54 | – | 10 | 174.6 | 8 | 26 | 152 |
| 2 9/16″ | 65.9 | 255 | 3 | – | 6.75 | 102.77 | 133 | 57.2 | 128.6 | 100 | 57.1 | – | 10 | 200 | 8 | 29 | 153 |
| 3 1/16″ | 78.6 | 290 | 3 | – | 7.54 | 119 | 154 | 64.3 | 154 | 122.2 | 63.5 | – | 10 | 230.2 | 8 | 32 | 154 |
| 4 1/16″ | 104 | 360 | 3 | – | 8.33 | 150.62 | 194 | 78.6 | 195.3 | 158.7 | 73 | – | 10 | 290.5 | 8 | 39 | 155 |
| 5 1/8″ | 131 | 420 | 3 | 9.5 | 9.53 | 176.66 | 225 | 98.5 | 244.5 | 200 | 81.8 | 6.4 | 16 | 342.9 | 12 | 42 | 169 |
| 7 1/16″ | 180.2 | 505 | 6 | 11.1 | 11.11 | 241.83 | 305 | 119.1 | 325.4 | 276.2 | 92.1 | 7.9 | 16 | 428.6 | 16 | 42 | 156 |
| 9 “ | 229.4 | 650 | 6 | 12.7 | 12.7 | 299.06 | 381 | 146.1 | 431.8 | 349.2 | 123.8 | 14.2 | 16 | 552.4 | 16 | 51 | 157 |
| 11″ | 280.2 | 815 | 6 | 14.3 | 14.29 | 357.23 | 454 | 187.4 | 584.2 | 427 | 235.7 | 12.7 | 16 | 711.2 | 20 | 54 | 158 |
| 13 5/8″ | 346.9 | 885 | 6 | 15.9 | 15.88 | 432.64 | 541 | 204.8 | 595.3 | 528.6 | 114.3 | 17.5 | 25 | 771.5 | 20 | 61 | 159 |
| 18 3/4″ | 477 | 1160 | 6 | 18.3 | 18.26 | 577.9 | 722 | 255.6 | 812.8 | 730.2 | 155.6 | 35.1 | 25 | 1016 | 20 | 80 | 164 |
1. RING NUMBER BX, 2. C should be the max value 3. Tolerance and Ring Gasket according to API 6A-20TH
API 6A-TYPE-6BX 103.5 MPA (15000 PSI) FLANGE
API 6A 6B weld neck flanges conforming to Table 36, Table 37 and Table 38 of API 6A (19th Edition) are available.
API 6A Type 6B 2000PSI Blind / Welding Neck Flange
Dimension of 2000PSI (13.8MPA) type 6B Blind and Welding Neck API 6A Flange
| Size | B | OD | C | K | P | E | T | Q | X | BC | N | H | LN | HL | JL | R/RX |
| 2 1/16″ | 53.2 | 165 | 3 | 108 | 82.55 | 7.9 | 33.4 | 25.4 | 84 | 127 | 8 | 20 | 81 | 60.3 | 53.3 | 23 |
| 2 9/16″ | 65.9 | 190 | 3 | 127 | 101.6 | 7.9 | 36.6 | 28.6 | 100 | 149.2 | 8 | 23 | 88 | 73 | 63.5 | 26 |
| 3 1/8″ | 81.8 | 210 | 3 | 146 | 123.83 | 7.9 | 39.7 | 31.8 | 117 | 168.3 | 8 | 23 | 91 | 88.9 | 78.7 | 31 |
| 4 1/16″ | 108.7 | 275 | 3 | 175 | 149.23 | 7.9 | 46.1 | 38.1 | 152 | 215.9 | 8 | 26 | 110 | 114.3 | 103.1 | 37 |
| 5 1/8″ | 131 | 330 | 3 | 210 | 180.98 | 7.9 | 52.4 | 44.5 | 189 | 266.7 | 8 | 29 | 122 | 141.3 | 122.9 | 41 |
| 7 1/16″ | 181.8 | 355 | 6 | 241 | 211.15 | 7.9 | 55.6 | 47.6 | 222 | 292.1 | 12 | 29 | 126 | 168.3 | 147.1 | 45 |
| 9″ | 229.4 | 420 | 6 | 302 | 269.88 | 7.9 | 63.5 | 55.6 | 273 | 349.3 | 12 | 32 | 141 | 219.1 | 199.1 | 49 |
| 11″ | 280.2 | 510 | 6 | 356 | 323.85 | 7.9 | 71.5 | 63.5 | 343 | 431.8 | 16 | 35 | 160 | 273 | 248.4 | 53 |
| 13 5/8″ | 346.9 | 560 | 6 | 413 | 381 | 7.9 | 74.7 | 66.7 | 400 | 489 | 20 | 35 | – | – | – | 57 |
| 16 3/4″ | 426.2 | 685 | 6 | 508 | 469.9 | 7.9 | 84.2 | 76.2 | 495 | 603.2 | 20 | 42 | – | – | – | 65 |
| 21 1/4″ | 540.5 | 815 | 6 | 635 | 584.2 | 9.7 | 98.5 | 88.9 | 610 | 723.9 | 24 | 45 | – | – | – | 73 |
1. RING NUMBER R or RX, 2. C should be the max value 3. Tolerance and Ring Gasket according to API 6A-20TH
API 6A Type 6BX 2000PSI Blind Flange
Dimension of 2000PSI (13.8MPA) type 6BX Blind API 6A Flange
| Size | OD | C | E1 | G | K | T | J1 | J4 | R | BC | N | H | BX |
| 26 3/4″ | 1040 | 6 | 21.4 | 768.33 | 805 | 126.3 | 835.8 | 9.7 | 16 | 952.5 | 20 | 48 | 167 |
| 30″ | 1120 | 6 | 23 | 862.3 | 908 | 134.2 | 931.9 | 17.5 | 16 | 1039.8 | 32 | 45 | 303 |
API 6A Type 6B 3000PSI Blind / Welding Neck Flange
Dimension of 3000PSI (20.7MPA) Type 6B Blind and API 6A Welding Neck Flange
| Size | B | OD | C | K | P | E | T | Q | X | BC | N | H | LN | HL | JL | R/RX |
| 2 1/16″ | 53.2 | 215 | 3 | 124 | 95.25 | 7.9 | 46.1 | 38.1 | 104.8 | 165.1 | 8 | 26 | 109.6 | 60.3 | 50 | 24 |
| 2 9/16″ | 65.9 | 245 | 3 | 137 | 107.95 | 7.9 | 49.3 | 41.3 | 123.8 | 190.5 | 8 | 29 | 112.7 | 73 | 59.7 | 27 |
| 3 1/8″ | 81.8 | 240 | 3 | 156 | 123.83 | 7.9 | 46.1 | 38.1 | 127 | 190.5 | 8 | 26 | 109.5 | 88.9 | 74.4 | 31 |
| 4 1/16″ | 108.7 | 290 | 3 | 181 | 149.23 | 7.9 | 52.4 | 44.4 | 158.8 | 235 | 8 | 32 | 122.2 | 114.3 | 98 | 37 |
| 5 1/8″ | 131 | 350 | 3 | 216 | 180.98 | 7.9 | 58.8 | 50.8 | 190.5 | 279.4 | 8 | 35 | 134.9 | 141.3 | 122.9 | 41 |
| 7 1/16″ | 181.8 | 380 | 6 | 241 | 211.15 | 7.9 | 63.5 | 55.6 | 235 | 317.5 | 12 | 32 | 147.6 | 168.3 | 147.1 | 45 |
| 9″ | 229.4 | 470 | 6 | 308 | 269.88 | 7.9 | 71.5 | 63.5 | 298.5 | 393.7 | 12 | 39 | 169.9 | 219.1 | 189.7 | 49 |
| 11″ | 280.2 | 545 | 6 | 362 | 323.85 | 7.9 | 77.8 | 69.9 | 368.3 | 469.9 | 16 | 39 | 192.1 | 273 | 237.2 | 53 |
| 13 5/8″ | 346.9 | 610 | 6 | 419 | 381 | 7.9 | 87.4 | 79.4 | 419.1 | 533.4 | 20 | 39 | – | – | – | 57 |
| 16 3/4″ | 426.2 | 705 | 6 | 524 | 469.9 | 11.2 | 100.1 | 88.9 | 508 | 616 | 20 | 45 | – | – | – | 66 |
| 20 3/4″ | 527.8 | 855 | 6 | 648 | 584.2 | 12.7 | 120.7 | 108 | 622.3 | 749.3 | 20 | 54 | – | – | – | 74 |
1. RING NUMBER R or RX, 2. C should be the max value 3. Tolerance and Ring Gasket according to API 6A-20TH
API 6A Type 6B 5000PSI Blind / Welding Neck Flange
Dimension of 5000PSI (34.5MPA) type 6B Blind and API 6A Welding Neck Flange
| Size | B | OD | C | K | P | E | T | Q | X | BC | N | H | LN | HL | JL | R/RX |
| 2 1/16″ | 53.2 | 215 | 3 | 124 | 95.25 | 7.9 | 46.1 | 38.1 | 104.8 | 165.1 | 8 | 26 | 109.5 | 60.3 | 43.7 | 24 |
| 2 9/16″ | 65.9 | 245 | 3 | 137 | 107.95 | 7.9 | 49.3 | 41.3 | 123.8 | 190.5 | 8 | 29 | 112.7 | 73 | 54.9 | 27 |
| 3 1/8″ | 81.8 | 265 | 3 | 168 | 136.53 | 7.9 | 55.6 | 47.7 | 133.3 | 203.2 | 8 | 32 | 125.4 | 88.9 | 67.5 | 35 |
| 4 1/16″ | 108.7 | 310 | 3 | 194 | 161.93 | 7.9 | 62 | 54 | 161.9 | 241.3 | 8 | 35 | 131.8 | 114.3 | 88.1 | 39 |
| 5 1/8″ | 131 | 375 | 3 | 229 | 193.68 | 7.9 | 81 | 73.1 | 196.8 | 292.1 | 8 | 42 | 163.5 | 141.3 | 110.3 | 44 |
| 7 1/16″ | 181.8 | 395 | 6 | 248 | 211.15 | 9.7 | 92.1 | 82.6 | 228.6 | 317.5 | 12 | 39 | 181 | 168.3 | 132.6 | 46 |
| 9″ | 229.4 | 485 | 6 | 318 | 269.88 | 11.2 | 103.2 | 92.1 | 292.1 | 393.7 | 12 | 45 | 223.8 | 219.1 | 173.8 | 50 |
| 11″ | 280.2 | 585 | 6 | 371 | 323.85 | 11.2 | 119.1 | 108 | 368.3 | 482.6 | 12 | 51 | 265.1 | 273.1 | 216.7 | 54 |
1. RING NUMBER R or RX, 2. C should be the max value 3. Tolerance and Ring Gasket according to API 6A-20TH
API 6A Type 6BX 10000PSI Blind / Welding Neck Flange
Dimension of 10000PSI(69.0MPA) type 6BX Blind and API 6A Welding Neck Flange
| Size | B | OD | C | E1 | Q | G | K | T | J1 | J2 | J3 | J4 | R | BC | N | H | BX |
| 1 13/16″ | 46.8 | 185 | 3 | – | 5.56 | 77.77 | 105 | 42.1 | 88.9 | 65.1 | 48.5 | – | 10 | 146.1 | 8 | 23 | 151 |
| 2 1/16″ | 53.2 | 200 | 3 | – | 5.95 | 86.23 | 111 | 44.1 | 100 | 74.7 | 51.6 | – | 10 | 158.8 | 8 | 23 | 152 |
| 2 9/16″ | 65.9 | 230 | 3 | – | 6.75 | 102.77 | 132 | 51.2 | 120.7 | 92.1 | 57.2 | – | 10 | 184.2 | 8 | 26 | 153 |
| 3 1/16″ | 78.6 | 270 | 3 | – | 7.54 | 119 | 152 | 58.4 | 142.1 | 110.2 | 63.5 | – | 10 | 215.9 | 8 | 29 | 154 |
| 4 1/16″ | 104 | 315 | 3 | – | 8.33 | 150.62 | 185 | 70.3 | 182.6 | 146.1 | 73.1 | – | 10 | 258.8 | 8 | 32 | 155 |
| 5 1/8″ | 131 | 360 | 3 | 9.5 | 9.53 | 176.66 | 221 | 79.4 | 223.8 | 182.6 | 81 | 6.4 | 10 | 300 | 12 | 32 | 169 |
| 7 1/16″ | 180.2 | 480 | 6 | 11.1 | 11.11 | 241.83 | 302 | 103.2 | 301.6 | 254 | 95.3 | 9.7 | 16 | 403.2 | 12 | 42 | 156 |
| 9 “ | 229.4 | 550 | 6 | 12.7 | 12.7 | 299.06 | 359 | 123.9 | 374.7 | 327.1 | 93.7 | 9.7 | 16 | 476.3 | 16 | 42 | 157 |
| 11″ | 280.2 | 655 | 6 | 14.3 | 14.29 | 357.23 | 429 | 141.3 | 450.9 | 400.1 | 103.2 | 14.2 | 16 | 565.2 | 16 | 48 | 158 |
| 13 5/8″ | 346.9 | 770 | 6 | 15.9 | 15.88 | 432.64 | 518 | 168.3 | 552.5 | 495.3 | 114.3 | 17.5 | 16 | 673.1 | 20 | 51 | 159 |
| 16 3/4″ | 426.2 | 870 | 6 | 8.3 | 8.33 | 478.33 | 576 | 168.3 | 655.6 | 601.7 | 76.2 | 30.2 | 19 | 776.3 | 24 | 51 | 162 |
| 18 3/4″ | 477 | 1040 | 6 | 18.3 | 18.26 | 577.9 | 697 | 223.1 | 752.5 | 674.7 | 155.6 | 25.4 | 16 | 925.5 | 24 | 61 | 164 |
| 21 1/4″ | 540.5 | 1145 | 6 | 19.1 | 19.05 | 647.88 | 781 | 241.3 | 847.7 | 762 | 165.1 | 31.8 | 21 | 1022.4 | 24 | 67 | 166 |
1. RING NUMBER BX, 2. C should be the max value 3. Tolerance and Ring Gasket according to API 6A-20TH
API 6A 6BX weld neck flanges conforming to Table 42 or Table 43 of API 6A (19th Edition) are available.
API 6A Type 6BX 15000PSI Blind / API 6A Welding Neck Flange
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| 6B welding neck flange | 6BX welding neck flange |
API 6A 6BX and API 6A 6B Blind Flanges
API 6A 6B blind flanges conforming to Table 36, Table 37 and Table 38 of API 6A (19th Edition) are available.
API 6A 6BX blind flanges conforming to Table 46 of API 6A (19th Edition) are available
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| API 6 A 6B blind flange | 6BX blind flange | 6BX blind flange with fluid cushion counterbore |
API 6A 6BX Target Flanges, Lead Filled
Target Flange: a special configuration of blind flange used downstream, facing upstream, to cushion and reduce the erosive affect of high velocity abrasive fluid. This flange has a counter bore filled with lead as illustrated below.
Target Flanges conforming to Table 44 and Table 45 of API 6A are available.
API 6A 6BX and 6B Test Flanges
API 6A 6B test flanges conforming to Table 36, Table 37 and Table 38 of API 6A (19th Edition) are available.
API 6A 6BX test flanges conforming to Table 44 and Table 45 of API 6A are available.
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| 6B test flange | 6BX test flange |
The difference between ASME/ANSI and API is the fabrication material and a higher rated API operating pressure.
ASME/ANSI flanges are commonly used in industrial process systems handling water, steam, air and gas. API flanges are manufactured for high strength operating refinery systems with products such as oil and explosive gases.
The flange standards API 6A and ASME/ANSI B16.5 have the same dimensions – but the API 6A flanges are rated for higher pressures as indicated below:
| API vs. ASME/ANSI Flanges with the same Dimensions | ||||
|---|---|---|---|---|
| Flange | Pressure Class Rating (psi) |
Nominal Size Range (inches) |
||
| ASME/ANSI B16.5 | API 6A | ASME/ANSI B16.5 | API 6A1) | |
| Weld neck | 600 | 2000 | 1/2 – 24 | 113/16 – 11 |
| 900 | 3000 | |||
| 1500 | 5000 | |||
| Blind and Threaded | 600 | 2000 | 113/16 – 211/4 | |
| 900 | 3000 | 113/16 – 203/4 | ||
| 1500 | 5000 | 113/16 – 11 | ||
1) In the old API standard, flanges ranged from 1 1/2 to 10(20) inches.
- 1 inch = 25.4 mm
