Views: 2 Author: Site Editor Publish Time: 2026-02-27 Origin: Site
In industrial sectors such as petrochemicals, power generation, and energy, the sealing reliability of piping systems directly impacts operational safety and efficiency. Flanges are crucial connecting components in piping systems, and their sealing performance depends on another critical component—the flange gasket.
The full title of the ASME B16.20 standard is "Metallic Gaskets for Pipe Flanges - Spiral-Wound Gaskets, Jacketed Gaskets, and Ring Joint Gaskets." It is used in conjunction with flange standards like ASME B16.5 (Pipe Flanges and Flanged Fittings) and ASME B16.47 (Large Diameter Steel Flanges), forming a complete specification system for flange connections.
This standard specifies in detail:
Gasket Types: Defines the construction types for various gaskets.
Dimensions and Tolerances: Provides precise requirements for key dimensions such as inside diameter (ID), outside diameter (OD), and thickness, along with their allowable deviations, ensuring a perfect match with the flange sealing faces.
Material Combinations: Guides the selection of filler materials, metal windings, jackets, and ring materials.
Marking and Acceptance: Specifies product identification methods and inspection criteria.
Choosing gaskets that meet the ASME B16.20 standard ensures optimal compatibility and interchangeability in dimensions and performance with corresponding ASME standard flanges. This is the first step towards achieving a "standardized seal."
According to ASME B16.20, flange gaskets are mainly divided into the following categories, each corresponding to different flange facing types and operating conditions:
Construction: Made by alternately winding pre-formed metal strip and non-metallic filler material (such as graphite, PTFE, ceramic fiber) around the circumference. Typically includes inner and outer metal guide rings for reinforcement.
Suitable Flanges: Primarily used with Raised Face (RF), Female/Male (FM/M), and Tongue/Groove (T/G) flanges.
Characteristics & Applications: Combines the strength of metal with the resilience of non-metallics, offering good compensation ability. Suitable for a wide range of temperatures and pressures, it is one of the most widely used gasket types in the petrochemical and power industries.
| Flange Size (NPS) | Outside Diameter of Gasket | Inside Diameter of Gasket by Class | Outside Diameter of Centering by Class | |||||||||||||
| Class 150 300 400 600 | Class 900 1500 2500 | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 | |
| 1/2 | 31.8 | 31.8 | 19.1 | 19.1 | [Note (5)] | 19.1 | [Note (5)] | 19.1 | 19.1 | 47.8 | 54.1 | [Note (5)] | 54.1 | [Note (5)] | 63.5 | 69.9 |
| 3/4 | 39.6 | 39.6 | 25.4 | 25.4 | [Note (5)] | 25.4 | [Note (5)] | 25.4 | 25.4 | 57.2 | 66.8 | [Note (5)] | 66.8 | [Note (5)] | 69.9 | 76.2 |
| 1 | 47.B | 47.8 | 31.8 | 31.8 | [Note (5)] | 31.8 | [Note (5)] | 31.8 | 31.8 | 66.8 | 73.2 | [Note (5)] | 73.2 | [Note (5)] | 79.5 | 85.9 |
| 1-1/4 | 60.5 | 60.5 | 47.8 | 47.8 | [Note (5)] | 47.8 | [Note (5)] | 39.6 | 39.6 | 76.2 | 82.6 | [Note (5)] | 82.6 | [Note (5)] | 88.9 | 104.9 |
| 1-1/2 | 69.9 | 69.9 | 54.1 | 54.1 | [Note (5)] | 54.1 | [Note (5)] | 47.8 | 47.8 | 85.9 | 95.3 | [Note (5)] | 95.3 | [Note (5)] | 98.6 | 117.6 |
| 2 | 85.9 | 85.9 | 69.9 | 69.9 | [Note (5)] | 69.9 | [Note (5)] | 58.7 | 58.7 | 104.9 | 111.3 | [Note (5)] | 111.3 | [Note (5)] | 143.0 | 146.1 |
| 2-1/2 | 98.6 | 98.6 | 82.6 | 82.6 | [Note (5)] | 82.6 | [Note (5)] | 69.9 | 69.9 | 124.0 | 130.3 | [Note (5)] | 130.3 | [Note (5)] | 165.1 | 168.4 |
| 3 | 120.7 | 120.7 | 101.6 | 101.6 | [Note (5)] | 1016 | 95.3 | 92.2 | 92.2 | 136.7 | 149.4 | [Note (5)] | 149.4 | 168.4 | 174.8 | 196.9 |
| 3-1/2 | 133.4 | - | 114.3 | 114.3 | [Note (5)] | 104.8 | [Note (5)] | - | - | 161.9 | 165.1 | [Note (5)] | 161.9 | [Note (5)] | - | - |
| 4 | 149.4 | 149.4 | 127.0 | 1270 | 120.7 | 120.7 | 120.7 | 117.6 | 117.6 | 174.8 | 181.1 | 177.8 | 193.8 | 206.5 | 209.6 | 235.0 |
| 5 | 177.8 | 177.8 | 155.7 | 155.7 | 147.6 | 147.6 | 147.6 | 143.0 | 143.0 | 196.9 | 215.9 | 212.9 | 241.3 | 247.7 | 254.0 | 279.4 |
| 6 | 209.6 | 209.6 | 182.6 | 182.6 | 174.8 | 174.8 | 174.8 | 171.5 | 171.5 | 222.3 | 251.0 | 247.7 | 266.7 | 289.1 | 282.7 | 317.5 |
| 8 | 263.7 | 257.3 | 233.4 | 233.4 | 225.6 | 225.6 | 222.3 | 215.9 | 215.9 | 279.4 | 308.1 | 304.8 | 320.8 | 358.9 | 352.6 | 387.4 |
| 10 | 3175 | 311.2 | 287.3 | 287.3 | 274.6 | 274.6 | 276.4 | 266.7 | 270.0 | 339.9 | 362.0 | 358.9 | 400.1 | 435.1 | 435.1 | 476.3 |
| 12 | 374.7 | 368.3 | 339.9 | 339.9 | 3272 | 327.2 | 323.9 | 323.9 | 317.5 | 409.7 | 422.4 | 419.1 | 457.2 | 498.6 | 520.7 | 549.4 |
| 14 | 406.4 | 400.1 | 371.6 | 371.6 | 362.0 | 362.0 | 355.6 | 362.0 | - | 450.9 | 485.9 | 482.6 | 492.3 | 520.7 | 577.9 | - |
| 16 | 463.6 | 457.2 | 422.4 | 422.4 | 412.8 | 412.8 | 412.8 | 406.4 | - | 514.4 | 539.8 | 536.7 | 565.2 | 574.8 | 641.4 | - |
| 18 | 527.1 | 520.7 | 474.7 | 474.7 | 469.9 | 469.9 | 463.6 | 463.6 | - | 549.4 | 596.9 | 593.9 | 612.9 | 638.3 | 704.9 | - |
| 20 | 577.9 | 571.5 | 525.5 | 525.5 | 520.7 | 520.7 | 520.7 | 514.4 | - | 606.6 | 654.1 | 647.7 | 682.8 | 698.5 | 755.7 | - |
| 24 | 685.8 | 679.5 | 628.7 | 628.7 | 628.7 | 628.7 | 628.7 | 616.0 | - | 7,176 | 774.7 | 768.4 | 790.7 | 838.2 | 901.7 | - |
NOTES:
(1)The gasket outside diamete olerance for NPS 1/2 through NPS 8 is ±0.8 mm〔±0.03 in.); for NPS 10 through NPS 24,+1.5mm,-0.8mm(+0.06in,-0.03 in.).
(2) Refer to para.SW-2.5 for required use of inner rings.
(3)The gasket inside diameter tolerance for NPS 1/2 through NPS 8 is±0.4mm(±0.016 in.); for NPS 10 through NPS 24,±0.8mm(±0.03 in.).
(4) The centering-ring outside diameter tolerance is ±0.8mm(±0.03 in.).
(5)There are no Class 400 flanges in NPS 1/2 trough NPS 3-1/2 (use Class 600);Class 900 flanges in NPS 1/2 through NPS 2-1/2 or in NPS 3-1/2 (use Cass1500); Clas1500 flanges in NPS 3-1/2;or Class 2500 flanges in NPS 3-1/2 or NPS 14 and larger.
| Flange Size （NPS） | Class150 | Class300 | Class400 | Class600 | Class900 | ||||||||||
| Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | ||||||
| Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | ||||||
| 26 | 673.1 | 704.9 | 774.7 | 685.8 | 736.6 | 835.2 | 685.8 | 736.6 | 831.9 | 685.8 | 736.6 | 866.9 | 685.8 | 736.6 | 882.7 |
| 28 | 723.9 | 755.7 | 831.9 | 736.6 | 787.4 | 898.7 | 736.6 | 787.4 | 892.3 | 736.6 | 787.4 | 914.4 | 736.6 | 7874 | 946.2 |
| 30 | 774.7 | 806.5 | 882.7 | 793.8 | 844.6 | 952.5 | 793.8 | 844.6 | 946.2 | 793.8 | 844.6 | 971.6 | 793.8 | 844.6 | 1009.7 |
| 32 | 825.5 | 860.6 | 939.8 | 850.9 | 901.7 | 1006.6 | 850.9 | 901.7 | 1003.3 | 850.9 | 901.7 | 1022.4 | 850.9 | 901.7 | 1073.2 |
| 34 | 876.3 | 911.4 | 990.6 | 901.7 | 952.5 | 1057.4 | 901.7 | 952.5 | 1054.1 | 901.7 | 952.5 | 1073.2 | 901.7 | 952.5 | 1136.7 |
| 36 | 927.1 | 968.5 | 1047.8 | 955.8 | 1006.6 | 1117.6 | 955.8 | 1006.6 | 1117.6 | 955.8 | 1006.6 | 1130.3 | 958.9 | 1009.7 | 1200.2 |
| 38 | 977.9 | 1019.3 | 1111.3 | 977.9 | 1016 | 1054.1 | 971.6 | 1022.4 | 1073.2 | 990.6 | 1041.4 | 1104.9 | 1035.1 | 1085.9 | 1200.2 |
| 40 | 1028.7 | 1070.1 | 1162.1 | 1022.4 | 1070.1 | 1114.6 | 1025.7 | 1076.5 | 1127.3 | 1047.8 | 1098.6 | 1155.7 | 1098.6 | 1149.4 | 1251 |
| 42 | 1079.5 | 1124 | 1219.2 | 1073.2 | 1120.9 | 1165.4 | 1076.5 | 1127.3 | 1178.1 | 1104.9 | 1155.7 | 1219.2 | 1149.4 | 1200.2 | 1301.8 |
| 44 | 1130.3 | 1178.1 | 1276.4 | 1130.3 | 11811 | 1219.2 | 1130.3 | 1181.1 | 1231.9 | 1162.1 | 1212.9 | 1270 | 1206.5 | 1257.3 | 1368.6 |
| 46 | 1181.1 | 1228.9 | 1327.2 | 1178.1 | 1228.9 | 1273.3 | 1193.8 | 1244.6 | 1289.1 | 1212.9 | 1263.7 | 1327.2 | 1270 | 1320.8 | 1435.1 |
| 48 | 1231.9 | 1279.7 | 1384.3 | 1235.2 | 1286 | 1324.1 | 1244.6 | 1295.4 | 1346.2 | 1270 | 1320.8 | 1390.7 | 1320.8 | 1371.6 | 1485.9 |
| 50 | 1282.7 | 1333.5 | 1435.1 | 1295.4 | 1346.2 | 1378 | 1295.4 | 1346.2 | 1403.4 | 1320.8 | 1371.6 | 1447.8 | - | - | - |
| 52 | 1333.5 | 1384.3 | 1492.3 | 1346.2 | 1397 | 1428.8 | 1346.2 | 1397 | 1454.2 | 1371.6 | 1422.4 | 1498.6 | - | - | - |
| 54 | 1384.3 | 1435.1 | 1549.4 | 1403.4 | 1454.2 | 1492.3 | 1403.4 | 1454.2 | 1517.7 | 1428.8 | 1479.6 | 1555.8 | - | - | - |
| 56 | 1435.1 | 1485.9 | 1606.6 | 1454.2 | 1505 | 1543.1 | 1454.2 | 1505 | 1568.5 | 1479.6 | 1530.4 | 1612.9 | - | - | - |
| 58 | 1485.9 | 1536.7 | 1663.7 | 1511.3 | 1562.1 | 1593.9 | 1505 | 1555.8 | 1619.3 | 1536.7 | 1587.5 | 1663.7 | - | - | - |
| 60 | 1536.7 | 1587.5 | 1714.5 | 1562.1 | 1612.9 | 1644.7 | 1568.5 | 1619.3 | 1682.8 | 1593.9 | 1644.7 | 1733.6 | - | - | - |
| Flange Size （NPS） | Class150 | Class300 | Class400 | Class600 | Class900 | ||||||||||
| Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | Gasket | Centering Ring Outside Diameter | ||||||
| Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | Inside Diameter | Outside Diameter | ||||||
| 26 | 673.1 | 698.5 | 725.4 | 673.1 | 711.2 | 771.7 | 666.8 | 698.5 | 746.3 | 663.7 | 714.5 | 765.3 | 692.2 | 749.3 | 838.2 |
| 28 | 723.9 | 749.3 | 776.2 | 723.9 | 762 | 825.5 | 714.5 | 749.3 | 800.1 | 704.9 | 755.7 | 8192 | 743 | 800.1 | 901.7 |
| 30 | 774.7 | 800.1 | 827 | 774.7 | 812.8 | 886 | 765.3 | 806.5 | 857.3 | 778 | 828.8 | 879.6 | 8065 | 8573 | 958.9 |
| 32 | 825.5 | 850.9 | 881.1 | 825.5 | 863.6 | 939.8 | 812.8 | 860.6 | 911.4 | 831.9 | 882.7 | 933.5 | 863.6 | 914.4 | 1016 |
| 34 | 876.3 | 908.1 | 935 | 876.3 | 914.4 | 993.9 | 866.9 | 911.4 | 962.2 | 8B9.0 | 939.8 | 997 | 920.8 | 971.6 | 1073.2 |
| 36 | 927.1 | 958.9 | 987.6 | 927.1 | 965.2 | 1047.8 | 917.7 | 965.2 | 1022.4 | 939.8 | 990.6 | 1047.8 | 946.2 | 997 | 1124 |
| 38 | 974.9 | 1009.7 | 1044.7 | 1009.7 | 1047.8 | 1098.6 | 971.6 | 1022.4 | 1073.2 | 990.6 | 1041.4 | 1104.9 | 1035.1 | 1085.9 | 1200.2 |
| 40 | 1022.4 | 10638 | 1095.5 | 1060.5 | 1098.6 | 11494 | 1025.7 | 1076.5 | 1127.3 | 1047.8 | 1098.6 | 1155.7 | 1098.6 | 1149.4 | 1251 |
| 42 | 1079.5 | 1114.6 | 1146.3 | 1111.3 | 1149.4 | 1200.2 | 1076.5 | 1127.3 | 1178.1 | 1104.9 | 1155.7 | 1219.2 | 1149.4 | 1200.2 | 1301.8 |
| 44 | 1124 | 1165.4 | 1197.1 | 1162.1 | 1200.2 | 1251 | 1130.3 | 1181.1 | 1231.9 | 1162.1 | 1212.9 | 1270 | 1206.5 | 1257.3 | 1368.6 |
| 46 | 1181.1 | 1224 | 1255.8 | 1216.2 | 1254.3 | 1317.8 | 1193.8 | 1244.6 | 1289.1 | 1212.9 | 1263.7 | 1327.2 | 1270 | 1320.8 | 1435.1 |
| 48 | 1231.9 | 1270 | 1306.6 | 1263.7 | 1311.4 | 1368.6 | 1244.6 | 1295.4 | 1346.2 | 1270 | 1320.8 | 1390.7 | 1320.8 | 1371.6 | 1485.9 |
| 50 | 1282.7 | 1325.6 | 1357.4 | 1317.8 | 1355.9 | 1419.4 | 1295.4 | 1346.2 | 1403.4 | 1320.8 | 1371.6 | 1447.8 | - | - | - |
| 52 | 1333.5 | 1376.4 | 1408.2 | 1368.6 | 1406.7 | 1470.2 | 1346.2 | 1397 | 1454.2 | 1371.6 | 1422.4 | 1498.6 | - | - | - |
| 54 | 1384.3 | 1422.4 | 1463.8 | 1403.4 | 1454.2 | 15304 | 1403.4 | 1454.2 | 1517.7 | 1428.8 | 1479.6 | 1555.8 | - | - | - |
| 56 | 1444.8 | 1478 | 1514.6 | 1479.6 | 1524 | 1593.9 | 1454.2 | 1505 | 1568.5 | 1479.6 | 1530.4 | 1612.9 | - | - | - |
| 58 | 1500.1 | 1528.8 | 1579.6 | 1535.2 | 1573.3 | 1655.8 | 1505 | 1555.8 | 1619.3 | 1536.7 | 1587.5 | 1663.7 | - | - | - |
| 60 | 1557.3 | 1586 | 1630.4 | 15890 | 1630.4 | 1706.6 | 1568.5 | 1619.3 | 1682.8 | 1593.9 | 1644.7 | 1733.6 | - | - | - |
Construction: Machined from solid metal into a specific cross-sectional shape, such as oval or octagonal.
Suitable Flanges: Specifically designed for Ring Type Joint (RTJ) flanges.
Characteristics & Applications: All-metal seal that generates extremely high sealing stress through line or surface contact. Suitable for extreme conditions involving high pressure, high temperature, hydrogen service, and thermal cycling. Commonly found in Christmas trees, high-pressure heat exchangers, and high-temperature steam pipelines.
| Ring Number | Average Pitch Diameter of Ring P mm (in.) | Wigth of Ring A mm (in.) | Height of Ring mm (in.) | Width of Flat on Octagonal Ring C mm (in.) | Radius in Octagonal Ring Ri mm (in.) | |
| Oval. B | Octagonal H | |||||
| R-11 | 34.14 (1.344) | 6.35 (0.250) | 11.2 (0.44) | 9.7 (0.38) | 4.32 (0.170) | 1.5 (0.06) |
| R-12 | 39.70 (1.563) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-13 | 42.88 (1.688) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-14 | 44.45 (1.750) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-15 | 47.63 (1.875) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-16 | 50.80 (2.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-17 | 57.15 (2.250) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-18 | 60.33 (2.375) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-19 | 65.10 (2.563) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-20 | 68.28 (2.688) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-21 | 72.24 (2.844) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-22 | 82.55 (3.250) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-23 | 82.55 (3.250) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-24 | 95.25 (3.750) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-25 | 101.60 (4.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-26 | 101.60 (4.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-27 | 107.95 (4.250) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-28 | 111.13 (4.375) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-29 | 114.30 (4.500) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-30 | 117.48 (4.625) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-31 | 123.83 (4.875) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-32 | 127.00 (5.000) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-33 | 131.78 (5.188) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-34 | 131.78 (5.188) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-35 | 136.53 (5.375) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-36 | 149.23 (5.875) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-37 | 149.23 (5.875) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-38 | 157.18 (6.188) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-39 | 161.93 (6.375) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| Ring Number | Average Pitch Diameter of Ring P mm (in.) | Wigth of Ring A mm (in.) | Height of Ring mm (in.) | Width of Flat on Octagonal Ring C mm (in.) | Radius in Octagonal Ring Ri mm (in.) | |
| Oval. B | Octagonal H | |||||
| R-40 | 171.45 (6.750) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-41 | 180.98 (7.125) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-42 | 190.50 (7.500) | 19.05 (0.750) | 25.4 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-43 | 193.68 (7.625) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-44 | 193.68 (7.625) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-45 | 211.15 (8.313) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-46 | 211.15 (8.313) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-47 | 228.60 (9.000) | 19.05 (0.750) | 25.4 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-48 | 247.65 (9.750) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-49 | 269.88 (10.625) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-50 | 269.88 (10.625) | 15.88 (0.625) | 22.4 (0.88) | 2.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-51 | 279.40 (11.000) | 22.23 (0.875) | 28.7 (1.13) | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-52 | 304.80 (12.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-53 | 323.85 (12.750) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-54 | 323.85 (12.750) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-55 | 342.90 (13.500) | 28.58 (1.125) | 36.6 (1.44) | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-56 | 381.00 (15.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-57 | 381.00 (15.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-58 | 381.00 (15.000) | 22.23 (0.875) | 28.7 (1.13) | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-59 | 396.88 (15.625) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-60 | 406.40 (16.000) | 31.75 (1.250) | 39.6 (1.56) | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-61 | 406.40 (16.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-62 | 419.10 (16.500) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-63 | 419.10 (16.500) | 25.40 (1.000) | 33.3 (1.31) | 31.8 (1.25) | 17.30 (0.681) | 2.3 (0.09) |
| R-64 | 454.03 (17.875) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-65 | 469.90 (18.500) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-66 | 469.90 (18.500) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-67 | 469.90 (18.500) | 28.58 (1.125) | 36.6 (1.44) | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-68 | 517.53 (20.375) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-69 | 533.40 (21.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-70 | 533.40 (21.000) | 19.05 (0.750) | 25.4 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-71 | 533.40 (21.000) | 28.58 (1.125) | 36.6 (1.44) | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-72 | 558.80 (22.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-73 | 584.20 (23.000) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-74 | 584.20 (23.000) | 19.05 (0.750) | 254 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-75 | 584.20 (23.000) | 31.75 (1.250) | 39.6 (1.56) | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-76 | 673.10 (26.500) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-77 | 692.15 (27.250) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-78 | 692.15 (27.250) | 25.40 (1.000) | 33.3 (1.31) | 31.8 (1.25) | 17.30 (0.681) | 2.3 (0.09) |
| R-79 | 692.15 (27.250) | 34.93 (1.375) | 44.5 (1.75) | 41.4 (1.63) | 24.82 (0.977) | 2.3 (0.09) |
| R-80 | 615.95 (24.250) | 7.95 (0.313) | - | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| Ring Number | Average Pitch Diameter of Ring P mm (in.) | Wigth of Ring A mm (in.) | Height of Ring mm (in.) | Width of Flat on Octagonal Ring C mm (in.) | Radius in Octagonal Ring Ri mm (in.) | |
| Oval. B | Octagonal H | |||||
| R-81 | 635.00 (25.000) | 14.30 (0.563) | … | 19.1 (0.75) | 9.58 (0.377) | 1.5 (0.06) |
| R-82 | 57.15 (2.250) | 11.13 (0.438) | … | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-84 | 63.50 (2.500) | 11.13 (0.438) | … | 16.0(0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-85 | 79.38 (3.125) | 12.70 (0.500) | … | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-86 | 90.50 (3.563) | 15.88 (0.625) | … | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-87 | 100.03 (3.938) | 15.88 (0.625) | … | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-88 | 123.83 (4.875) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-89 | 114.30 (4.500) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-90 | 155.58 (6.125) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-91 | 260.35 (10.250) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-92 | 228.60 (9.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-93 | 749.30 (29.500) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-94 | 800.10 (31.500) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-95 | 857.25 (33.750) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-96 | 914.40 (36.000) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-97 | 965.20 (38.000) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-98 | 1022.35 (40.250) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-99 | 234.95 (9.250) | 11.13 (0.438) | … | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-100 | 749.30 (29.500) | 28.58 (1.125) | … | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-101 | 800.10 (31.500) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-102 | 857.25 (33.750) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-103 | 914.40 (36.000) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-104 | 965.20 (38.000) | 34.93 (1.375) | … | 41.4 (1.63) | 24.82 (0.977) | 2.3 (0.09) |
| R-105 | 1022.35 (40.250) | 34.93 (1.375) | … | 41.4 (1.63) | 24.82 (0.977) | 2.3 (0.09) |
GENERAL NOTE: Tolerances:
23 deg= angle,±0 deg 30 min(±1/2 deg)
A=width of ring,±0.20mm(±0.008in.)
B,H= height of ring,+1.3mm,-0.5mm(+0.05 in.,-0.02 in.)
Variation in height throughout the entire circumference of any given ringshall not exceed 0.5mm(0.02 in.) within these tolerances.
C=width of flat on octagonal ring,±0.20mm(±0.008 in.)
P= average pitch diameter of ring,±0.18mm(±0.007 in.]
Ri=radius in ring,±0.5mm(±0.02 in.)
| Ring Number | Outside Diameter of Ring O.D mm (in.) | Width of Ring A mm (in.) | Width of Flat C mm (in.) | Height of Outside Bevel D mm (in.) | Height of Ring H mm (in.) | Radius in Octagonal Ring Ri mm (in.) | Hole Size E mm (in.) |
| RX-20 | 76.20 (3.000) | 8.74 (0.344) | 4.62 (0.182) | 3.18 (0.125) | 19.05 (0.750) | 1.5 (0.06) | - |
| RX-23 | 93.27 (3.672) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1000) | 1.5 (0.06) | - |
| RX-24 | 105.97 (4.172) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-25 | 109.55 (4.313) | 8.74 (0.344) | 4.62 (0.182) | 3.18 (0.125) | 19.05 (0.750) | 1.5 (0.06) | - |
| RX-26 | 111.91 (4.406) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-27 | 118.26 (4.656) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-31 | 134.54 (5.297) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-35 | 147.24 (5.797) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-37 | 159.94 (6.297) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-39 | 172.64 (6.797) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-41 | 191.69 (7.547) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-44 | 204.39 (8.047) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-45 | 221.84 (8.734) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-46 | 222.25 (8.750) | 13.49 (0.531) | 6.68 (0.263) | 4.78 (0.188) | 28.58 (1.125) | 1.5 (0.06) | - |
| RX-47 | 245.26 (9.656) | 19.84 (0.781) | 10.34 (0.407) | 6.88 (0.271) | 41.28 (1.625) | 2.3 (0.09) | - |
| RX-49 | 280.59 (11.047) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1000) | 1.5 (0.06) | - |
| RX-50 | 283.36 (11.156) | 16.66 (0.656) | 8.51 (0.335) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| RX-53 | 334.57 (13.172) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-54 | 337.34 (13.281) | 16.66 (0.656) | 8.51 (0.335) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| RX-57 | 391.72 (15.422) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-63 | 441.73 (17.391) | 27.00 (1.063) | 14.78 (0.582) | 8.46 (0.333) | 50.80 (2.000) | 2.3 (0.09) | - |
| RX-65 | 480.62 (18.922) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-66 | 483.39 (19.031) | 16.66 (0.656) | 8.51 (0.335) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| RX-69 | 544.12 (21.422) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1000) | 1.5 (0.06) | - |
| RX-70 | 550.06 (21.656) | 19.84 (0.781) | 10.34 (0.407) | 6.88 (0.271) | 41.28 (1.625) | 2.3 (0.09) | - |
| RX-73 | 596.11 (23.469) | 13.49 (0.531) | 6.68 (0.263) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| Ring Number | Outside Diameter of Ring O.D mm (in.) | Width of Ring A mm (in.) | Width of Flat C mm (in.) | Height of Outside Bevel D mm (in.) | Height of Ring H mm (in.) | Radius in Octagonal Ring Ri mm (in.) | Hole Size E mm (in.) |
| RX-74 | 600.86 (23.656) | 19.84 (0.781) | 10.34 (0.407) | 6.88 (0.271) | 41.28 (1.625) | 2.3 (0.09) | - |
| RX-82 | 67.87 (2.672) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | 1.5 (0.06) |
| RX-84 | 74.22 (2.922) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | 1.5 (0.06) |
| RX-85 | 90.09 (3.547) | 13.49 (0.531) | 6.68 (0.263) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | 1.5 (0.06) |
| RX-86 | 103.58 (4.078) | 15.09 (0.594) | 8.51 (0.335) | 4.78 (0.188) | 28.58 (1.125) | 1.5 (0.06) | 2.3 (0.09) |
| RX-87 | 113.11 (4.453) | 15.09 (0.594) | 8.51 (0.335) | 4.78 (0.188) | 28.58 (1.125) | 1.5 (0.06) | 2.3 (0.09) |
| RX-88 | 139.29 (5.484) | 17.48 (0.688) | 10.34 (0.407) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | 3.0 (0.12) |
| RX-89 | 129.77 (5.109) | 18.26 (0.719) | 10.34 (0.407) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | 3.0 (0.12) |
| RX-90 | 174.63 (6.875) | 19.84 (0.781) | 12.17 (0.479) | 7.42 (0.292) | 44.45 (1.750) | 2.3 (0.09) | 3.0 (0.12) |
| RX-91 | 286.94 (11.297) | 30.18 (1.188) | 19.81 (0.780) | 7.54 (0.297) | 45.24 (1.781) | 2.3 (0.09) | 3.0 (0.12) |
| RX-99 | 245.67 (9.672) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-201 | 51.46 (2.026) | 5.74 (0.226) | 3.20 (0.126) | 1.45 (0.057) | 11.30 (0.445) | 0.5 (0.02) | - |
| RX-205 | 62.31 (2.453) | 5.56 (0.219) | 3.05 (0.120) | 1.83 (0.072) | 11.10 (0.437) | 0.5 (0.02) | - |
| RX-210 | 97.64 (3.844) | 9.53 (0.375) | 5.41 (0.213) | 3.18 (0.125) | 19.05 (0.750) | 0.8 (0.03) | - |
| RX-215 | 140.89 (5.547) | 11.91 (0.469) | 5.33 (0.210) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
GENERAL NOTE: Tolerances:
23 deg=angle,±0 deg, 30 min(±1/2 deg)
A=width of ring,+0.20mm,-0.00 mm(+0.008in.,-0in.)
Variation in width throughout the entire circumference of any ring shall not exceed 0.10mm(0.004 in.) within these tolerances.
C=width of flat,+0.15mm,-0.00 mm(+0.006 in.-0 in.)
D=height of outside bevel,+0.0 mm,-0.76mm(+0 in.,-0.030 in.)
E=hole size,±0.5 mm(±0.02 in.)
H=height of ring,+0.20mm,-0.00 mm(+0.008 in.,-0 in.)
Variation in height throughout the entire circumference of any ring shall not exceed 0.10mm(0.004 in.) within these tolerances.
0.D.= outside diameter of ring,+0.51mm,-0.00 mm(+0.020 in.,-0 in.)
Ri=radius of ring,±0.5 mm(±0.02 in.)
| Ring Number | Nominal mm (in.) | Outside Diameter of Ring O.D mm (in.) | Height of Ring H mm (in.) | Width of Ring A mm (in.) | Outside Diameter of Flat O.D.T mm (in.) | Width of Flat C mm (in.) | Hole Size D mm (in.) |
| BX-150 | 43 (1-11/6) | 72.19 (2.842) | 9.30 (0.366) | 9.30 (0.366) | 70.87 (2.790) | 7.98 (0.314) | 1.5 (0.06) |
| BX-151 | 46 (1-13/6) | 76.40 (3.008) | 9.63 (0.379) | 9.63 (0.379) | 75.03 (2.954) | 8.26 (0.325) | 1.5 (0.06) |
| BX-152 | 52 (2-1/16) | 84.68 (3.334) | 10.24 (0.403) | 10.24 (0.403) | 83.24 (3.277) | 8.79 (0.346) | 1.5 (0.06) |
| BX-153 | 65 (2-9/16) | 100.94 (3.974) | 11.38 (0.448) | 11.38 (0.448) | 99.31 (3.910) | 9.78 (0.385) | 1.5 (0.06) |
| BX-154 | 78 (3-1/16) | 116.84 (4.600) | 12.40 (0.488) | 12.40 (0.488) | 115.09 (4.531) | 10.64 (0.419) | 1.5 (0.06) |
| BX-155 | 103 (4-1/16) | 147.96 (5.825) | 14.22 (0.560) | 14.22 (0.560) | 145.95 (5.746) | 12.22 (0.481) | 1.5 (0.06) |
| BX-156 | 179 (7-1/16) | 237.92 (9.367) | 18.62 (0.733) | 18.62 (0.733) | 235.28 (9.263) | 15.98 (0.629) | 3.0 (0.12) |
| BX-157 | 229 (9) | 294.46 (11.593) | 20.98 (0.826) | 20.98 (0.826) | 291.49 (11.476) | 18.01 (0.709) | 3.0 (0.12) |
| BX-158 | 279 (11) | 352.04 (13.860) | 23.14 (0.911) | 23.14 (0.911) | 348.77 (13.731) | 19.86 (0.782) | 3.0 (0.12) |
| BX-159 | 346 (13-5/8) | 426.72 (16.800) | 25.70 (1.012) | 25.70 (1.012) | 423.09 (16.657) | 22.07 (0.869) | 3.0 (0.12) |
| BX-160 | 346 (13-5/8) | 402.59 (15.850) | 23.83 (0.938) | 13.74 (0.541) | 399.21 (15.717) | 10.36 (0.408) | 3.0 (0.12) |
| BX-161 | 422 (16-5/8) | 491.41 (19.347) | 28.07 (1.105) | 16.21 (0.638) | 487.45 (19.191) | 12.24 (0.482) | 3.0 (0.12) |
| BX-162 | 422 (16-5/8) | 475.49 (18.720) | 14.22 (0.560) | 14.22 (0.560) | 473.48 (18.641) | 12.22 (0.481) | 1.5 (0.06) |
| BX-163 | 476 (18-3/4) | 556.16 (21.896) | 30.10 (1.185) | 17.37 (0.684) | 551.89 (21.728) | 13.11 (0.516) | 3.0 (0.12) |
| BX-164 | 476 (18-3/4) | 570.56 (22.463) | 30.10 (1.185) | 24.59 (0.968) | 566.29 (22.295) | 20.32 (0.800) | 3.0 (0.12) |
| BX-165 | 540 (21-1/4) | 624.71 (24.595) | 32.03 (1.261) | 18.49 (0.728) | 620.19 (24.417) | 13.97 (0.550) | 3.0 (0.12) |
| BX-166 | 540 (21-1/4) | 640.03 (25.198) | 32.03 (1.261) | 26.14 (1.029) | 635.51 (25.020) | 21.62 (0.851) | 3.0 (0.12) |
| BX-167 | 680 (26-3/4) | 759.36 (29.896) | 35.86 (1.412) | 13.11 (0.516) | 754.28 (29.696) | 8.03 (0.316) | 1.5 (0.06) |
| BX-168 | 680 (26-3/4) | 765.25 (30.128) | 35.86 (1.412) | 16.05 (0.632) | 760.17 (29.928) | 10.97 (0.432) | 1.5 (0.06) |
| BX-169 | 130 (5-1/8) | 173.51 (6.831) | 15.85 (0.624) | 12.93 (0.509) | 171.27 (6.743) | 10.69 (0.421) | 1.5 (0.06) |
| BX-170 | 168 (6-5/8) | 218.03 (8.584) | 14.22 (0.560) | 14.22 (0.560) | 216.03 (8.505) | 12.22 (0.481) | 1.5 (0.06) |
| BX-171 | 218 (8-9/16) | 267.44 (10.529) | 14.22 (0.560) | 14.22 (0.560) | 265.43 (10.450) | 12.22 (0.481) | 1.5 (0.06) |
| BX-172 | 283 (11-5/32) | 333.07 (13.113) | 14.22 (0.560) | 14.22 (0.560) | 331.06 (13.034) | 12.22 (0.481) | 1.5 (0.06) |
| BX-303 | 762 (30) | 852.75 (33.573) | 37.95 (1.494) | 16.97 (0.668) | 847.37 (33.361) | 11.61 (0.457) | 1.5 (0.06) |
GENERAL NOTE:
(a) Radius, R, shall be 8% to 12% of the gasket height,H.
(b) Tolerances:
23 deg= angle,±0 deg 15 min(±V4 deg)
A=width of ring,+0.20mm,-0.00 mm(+0.008 in.,-0 in.)
Variation in width throughout the entire circumference of any ring shall not exceed 0.10mm(0.004in.) within these tolerances.
C=width of flat,+0.15mm,-0.00 mm(+0.006 in.,-0 in.)
D=hole size,±0.5 mm(±0.02 in.)
H=height of ring,+0.20mm,-0.00 mm(+0.008 in.,-0 in.)
Variation in height throughout the entire circumference of any ring shall not exceed 0.10mm〔0.004in.) within these tolerances.
0.D.= outside diameter of ring,+0.00 mm,-0.15mm(+0 in.,-0.005 in.)
0.D.T.=outside diameter of flat,±0.05 mm(±0.002 in.)
R=radius of ring [see General Note (a)]
Construction: Formed by completely covering (jacketing) a non-metallic filler material (e.g., graphite, ceramic fiber sheet) with a soft metal jacket (e.g., copper, aluminum, soft steel, stainless steel).
Suitable Flanges: Can be used with various flange faces, including Raised Face (RF) and Flat Face (FF).
Characteristics & Applications: The metal jacket protects the internal filler material from media attack and mechanical damage while providing good resilience. Often used in heat exchangers, valve bonnets, and certain corrosive media environments.
The ASME B16.20 standard imposes strict requirements on gasket dimensions. For example:
For spiral-wound gaskets, the standard specifies the Inside Diameter (ID), Outside Diameter (OD), and basic thickness that match flanges of different pressure classes (Class) and nominal pipe sizes (NPS).
For ring joint gaskets, it strictly defines the ring's width, height, inside/outside diameters, and the critical cross-sectional shape dimensions (such as the octagonal pitch diameter).
Tolerance ranges (e.g., ±0.13 mm, ±0.25 mm) are tightly controlled to ensure the gasket fits correctly into the flange sealing groove or positions correctly on the flange face. This prevents installation issues, uneven compression, or insufficient sealing stress caused by dimensional deviations, which could lead to leaks.
Flange sealing is a system comprising the "Flange-Bolt-Gasket" assembly. The flange gasket plays a vital role in this system:
Initial Seal: Under bolt preload, the gasket deforms elastically or plastically, filling microscopic irregularities on the flange sealing faces to create an initial seal.
Operational Seal: When the pipeline experiences internal pressure, temperature changes, or other factors that tend to separate the flanges, the gasket relies on residual compressive stress and its own recovery ability to maintain sufficient sealing stress, preventing media leakage.
Compensation: The gasket can compensate for gap changes caused by temperature fluctuations, mechanical vibration, or minor flange misalignment.
Therefore, a correctly selected, quality-assured, and properly installed ASME B16.20 flange gasket is the most important guarantee of the sealing performance of the entire flange connection.
Flange gaskets based on the ASME B16.20 standard are used in any industrial field involving standard flange connections:
Oil & Gas: Upstream exploration, refineries, long-distance pipelines.
Chemical & Petrochemical: Various reactors, towers, heat exchangers, process piping.
Power Industry: Steam systems in thermal power plants, auxiliary systems in nuclear power plants.
Shipbuilding: Marine propulsion systems and piping.
Other Industries: Special media piping in sectors like pulp & paper, pharmaceuticals, and food processing.
When selecting an ASME B16.20 flange gasket, it is essential to make the most suitable choice based on the flange type, media characteristics, temperature and pressure parameters, and specific operating conditions, following the guidance of the standard.
