ASME B16.20 Type RX Ring Gasket
ASME B16.20 Type RX ring gaskets are pressure-energized ring-type joint (RTJ) gaskets used with API 6B RTJ flanges. They are designed with a more advanced sealing geometry than Type R gaskets, providing enhanced sealing performance as internal pressure increases.
Types: RX (pressure-energized RTJ profile)
Materials: Soft iron, carbon and low alloy steels, stainless steels, and corrosion-resistant alloys (CRAs)
Standards: API 6A, ASME B16.20
ASME B16.20 Type RX ring gasket is a precision-machined metal gasket engineered to create a high-integrity, metal-to-metal seal in RTJ flanges. Once installed in the flange groove, the RX gasket compresses and then becomes pressure-energized, meaning internal system pressure improves the sealing effectiveness, making it ideal for higher-pressure and more demanding applications.
The Type RX gasket is widely used in industries requiring high-pressure sealing, such as oil & gas, petrochemical, refining, and offshore operations, where enhanced performance and reliability are essential.
Types of ASME B16.20 Type RX Ring Gaskets
They are available in the following variations:
Standard RX Rings (RX-11 to RX-215)
- The most common type.
- Covers a full range of standard RTJ sizes.
- Used for general high-pressure piping, valves, wellheads, and flow control systems.
RX Rings with Pressure-Relief Hole
- Includes a small drilled pressure-relief hole.
- Prevents pressure lock during operation.
- Required where trapped pressure could cause seal failure.
ASME B16.20 Type RX Ring Gaskets Dimensions
ASME B16.20 Type RX ring gaskets are pressure-energized RTJ (Ring Type Joint) gaskets designed for API 6B flanges. They look similar to Type R but include a built-in pressure-energizing feature, providing better sealing performance at higher pressures.
| Ring Number | Outside Diameter of Ring, 0.D. | Width of Ring, A | Width of Flat, C | Height of Outside Bevel, D | Height of Ring, H | Radius in Octagonal Ring,R1 | Hole Size, E |
|---|---|---|---|---|---|---|---|
| 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(1.000) | 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(1.000) | 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(1.000) | 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) | |
| 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)[Note (2)] | |
| RX-205 | 62.31(2.453) | 5.56(0.219) | 3.05(0.120) | 1.83(0.072)[Note (3)] | 11.10(0.437) | 0.5(0.02)[Note (2)] | |
| RX-210 | 97.64(3.844) | 9.53(0.375) | 5.41(0.213) | 3.18(0.125)[Note (3)] | 19.05(0.750) | 0.8(0.03) [Note (2)] | |
| RX-215 | 140.89(5.547) | 11.91(0.469) | 5.33(0.210) | 4.24(0.167)[Note (3)] | 25.40(1.000) | 1.5(0.06)[Note (2)] |
GENERAL NOTE: Tolerances:
- 23 deg = angle, ±0 deg, 30 min (±1 /2 deg)
- A = width of ring, +0.20 mm, −0.00 mm (+0.008 in., −0 in.)
- Variation in width throughout the entire circumference of any ring shall not exceed 0.10 mm (0.004 in.) within these tolerances.
- C = width of flat, +0.15 mm, −0.00 mm (+0.006 in., −0 in.)
- D = height of outside bevel, +0.0 mm, −0.76 mm (+0 in., −0.030 in.)
- E = hole size, ±0.5 mm (±0.02 in.)
- H = height of ring, +0.20 mm, −0.00 mm (+0.008 in., −0 in.)
- Variation in height throughout the entire circumference of any ring shall not exceed 0.10 mm (0.004 in.) within these tolerances.
- O.D. = outside diameter of ring, +0.51 mm, −0.00 mm (+0.020 in., −0 in.)
- R1 = radius of ring, ±0.5 mm (±0.02 in.)
NOTES:
- Rings RX-82 throughRX-91 require only one pressure passage hole as illustrated. The centerline ofthe hole shall be located atthe midpoint of dimension C.
- Tolerance on these dimensions is +0.5 mm, −0.0 mm (+0.02 in., −0 in.).
- Tolerance on these dimensions is +0.00 mm, −0.38 mm (+0 in., −0.015 in.).
Pipe Size,NPS,by API 6B Pressure Class
| Ring Number | 720-960 and 2000 [Note(1)] | 2900 [Note(1)] | 3000 | 5000 |
|---|---|---|---|---|
| RX-20 | 1 1/2 | 1 1/2 | 1 1/2 | |
| RX-23 | 2 | |||
| RX-24 | 2 | 2 | ||
| RX-25 | 3 1/8 | |||
| RX-26 | 2 1/2 | |||
| RX-27 | 2 1/2 | 2 1/2 | ||
| RX-31 | 3 | 3 | ||
| RX-35 | 3 | |||
| RX-37 | 4 | 4 | ||
| RX-39 | 4 | |||
| RX-41 | 5 | 5 | ||
| RX-44 | 5 | |||
| RX-45 | 6 | 6 | ||
| RX-46 | 6 | |||
| RX-47 | 8 [Note(2)] | |||
| RX-49 | 8 | 8 | ||
| RX-50 | 8 | |||
| RX-53 | 10 | 10 | ||
| RX-54 | 10 | |||
| RX-57 | 12 | 12 | ||
| RX-63 | 14 | |||
| RX-65 | 16 | |||
| RX-66 | 16 | |||
| RX-69 | 18 | |||
| RX-70 | 18 | |||
| RX-73 | 20 | * | ||
| RX-74 | 20 | |||
| RX-82 | 1 | |||
| RX-84 | 1 1/2 | |||
| RX-85 | 2 | |||
| RX-86 | 2 1/2 | |||
| RX-87 | 3 | |||
| RX-88 | 4 | |||
| RX-89 | 3 1/2 | |||
| RX-90 | 5 | |||
| RX-91 | 10 | |||
| RX-99 | 8[Note (2)] | 8 [Note (2)] | ||
| RX-201 | 1 3/8 | |||
| RX-205 | 1 13/16 | |||
| RX-210 | 2 9/16 | |||
| RX-215 | 4 1/16 | |||
NOTES:
- Class 720, 960, and 2900 flanges to API 6B are obsolete. Data are for information only.
- Crossover flange connection.
Materials Used for ASME B16.20 Type r Ring Gaskets
- Soft Iron
- Carbon Steel & Low Alloy Steels
- Stainless Steel
In the oil and gas, chemical, and seawater system industries, CRA (Corrosion-Resistant Alloy) refers to special metallic materials with high corrosion resistance, such as:
- Inconel series (e.g., 625, 718)
- Incoloy series (e.g., 825, 925)
- Monel 400
- Hastelloy series (e.g., C276, C22)
- Duplex / Super Duplex (e.g., 2205, 2507)
- 904L
- Alloy 20
- Titanium alloys
| Material | Identification | DIN | B.S. | ASTM / UNS | Hardness Max (HB) | Hardness Max (HRB) | Min Temp (C) | Max Temp (C) | Density (g/cm3) |
|---|---|---|---|---|---|---|---|---|---|
| Soft Iron | D | 90 | 56 | -60 | 500 | 7.85 | |||
| Low Carbon Steel | S | 120 | 68 | -40 | 500 | 7.85 | |||
| ASTM A182 F5 | F5 | 1.7362 | F5 | 130 | 72 | -40 | 650 | 7.9 | |
| SS304 | S304 | 1.4301 | 304S15/16 | S30400 | 160 | 83 | -250 | 550 | 7.9 |
| SS304L | S304L | 1.4306 | 304S11 | S30403 | 160 | 83 | -250 | 550 | 7.9 |
| SS309 | S309 | 1.4828 | 309S24 | S30900 | 160 | 83 | -250 | 1000 | 7.9 |
| SS316 | S316 | 1.4401 | 316S16 | S31600 | 160 | 83 | -100 | 1000 | 7.9 |
| SS316L | S316L | 1.4404 | 316S11/13 | S31603 | 160 | 83 | -100 | 550 | 7.9 |
| SS316Ti | S316Ti | 1.4571 | 320S31 | S31635 | 160 | 83 | -100 | 550 | 7.8 |
| SS321 | S321 | 1.4541 | 321S12/49/87 | S32100 | 160 | 83 | -250 | 850 | 7.9 |
| SS347 | S347 | 1.455 | 347S31 | S34700 | 160 | 83 | -250 | 850 | 7.9 |
| SS410 | S410 | 1.4006 | 410S21 | S41000 | 170 | 86 | -20 | 650 | 7.8 |
| 254 SMO | 6Mo | 1.4547 | S31254 | 180 | 89 | -100 | 550 | 8 | |
| 904L | S904L | 1.4539 | SUS890L | N08904 | 180 | 89 | -250 | 400 | 8 |
| Duplex F51 | F51 | 1.4462 | 31853 | S31803 / S32205 | 230 | 99 | -40 | 300 | 7.8 |
| Super Duplex F53 | F53 | 1.441 | S32750 | 230 | 99 | -40 | 300 | 7.8 | |
| Super Duplex F55 | F55 | 1.4501 | S32760 | 250 | 102 | -40 | 300 | 7.8 | |
| Brass (CuZn37) | CuZn37 | 2.0321 | CZ108 | C27200 | 60 | -100 | 350 | 8.5 | |
| Nickel 200 | Ni200 | 2.4066 | NA11 | N02200 | 110 | 62 | -250 | 600 | 8.9 |
| Monel 400 | MONEL400 | 2.436 | NA13 | N04400 | 160 | 83 | -250 | 600 | 8.8 |
| Inconel 600 | INC600 | 2.4816 | NA14 | N06600 | 160 | 83 | -100 | 950 | 8.4 |
| Inconel 625 | INC625 | 2.4856 | NA21 | N06625 | 210 | 95 | -50 | 650 | 8.44 |
| Inconel 718 | INC718 | N07718 | 160 | 83 | -125 | 700 | 8.24 | ||
| Incoloy 800 | INC800 | 1.4876 | NA15 | N08800 | 160 | 83 | -100 | 850 | 8 |
| Incoloy 825 | INC825 | 2.4858 | NA16 | N08825 | 195 | 92 | -100 | 450 | 8.14 |
| Hastelloy B2 | HB2 | 2.4617 | N10665 | 230 | 99 | -200 | 450 | 9.2 | |
| Hastelloy C276 | HC276 | 2.4819 | N10276 | 210 | 95 | -200 | 400 | 8.9 | |
| Titanium Grade 2 | Ti2 | 3.7035 | TA2 | R50400 | 215 | 96 | -250 | 350 | 4.5 |
Application
ASME B16.20 Type RX ring gaskets are pressure-energized RTJ gaskets designed for high-pressure, high-temperature, and critical sealing environments. They are primarily used with API 6B flanges and are suitable for demanding industrial operations where absolute leak integrity is required.
- Oil & Gas Wellhead Equipment
- High-Pressure Valves & Connectors
- Drilling & Completion Systems
- Petrochemical & Refinery Services
- Subsea & Offshore Installations
- High-Pressure Pipelines & Flowlines
Markings & Identification
Standard markings typically include:
- Gasket Type – e.g., RX
- Ring Number / Size – e.g., RX-47
- Material Grade – e.g., CS, SS316, Inconel 625, Duplex, etc.
- Manufacturer’s Name or Trademark
- Heat / Batch Number – ensures full traceability
- Standard Reference – ASME B16.20
- Hardness (when required)
Example marking:
RX-47 • SS316 • ASME B16.20 • Heat No. 12345 • MillsForge
Why Choose MillsForge for ASME B16.20 Type RX Ring Gaskets?
MillsForge provides high-performance ASME B16.20 Type RX Ring Gaskets, engineered for high-pressure RTJ flange applications up to API 6A / ASME Class 5000. Manufactured under ISO 9001:2005 quality control, our RX gaskets are designed with a pressure-energized sealing structure that delivers superior tightness under increasing internal pressure.
What We Offer
Fully compliant ASME B16.20 / Type RX ring gaskets
Pressure-energized sealing design for high-pressure systems
Wide selection of materials for sour-service, H₂S, and offshore corrosion environments
Precision machining with controlled hardness and strict dimensional tolerances
Fast delivery and worldwide supply capability
MillsForge ensures every Type RX ring gasket meets the toughest industry requirements for sealing performance, reliability, and operational safety.
