ASTM A106 Gr B Ring Type Joint FlangeASTM A105 · ASME B16.5 · Manufacturer, stockist & exporter, India
SA-106 Gr B · Seamless carbon steel pipe · RTJ
An ASTM A106 Gr B ring type joint flange is a flange with a machined groove for a metal ring gasket, for use with ASTM A106 Gr B pipe. ASTM A106 Gr B itself is a pipe or plate specification, so the matching ring type joint flange is made to ASTM A105 — which is what we supply for A106 B lines. RTJ flanges are used for high pressure and temperature — typically Class 600 and above, and on wellhead and API equipment. The metal ring deforms into the groove to seal.
- ASTM A105
- ASME B16.5
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an ASTM A106 Gr B Ring Type Joint Flange?
- What it is
- A flange with a machined groove for a metal ring gasket
- Material
- ASTM A105
- Dimensions
- ASME B16.5 · ASME B16.20
- Grade
- ASTM A106 Gr B
- Best at
- High-temperature process and steam piping in refineries and power plants
ASTM A106 Gr B Ring Type Joint Flange Specification
| Product | ASTM A106 Gr B Ring Type Joint Flange |
|---|---|
| Material standard | ASTM A105 |
| Dimensional standard | ASME B16.5 · ASME B16.20 |
| Sizes | ½" – 24" (ASME B16.5) · 26" – 60" (ASME B16.47) |
| Pressure class | Class 150, 300, 400, 600, 900, 1500, 2500 · PN 6 – PN 100 |
| Facing | RF · FF · RTJ · tongue & groove |
| Bore | To match pipe schedule (state on order) |
| Testing | Chemical & mechanical per heat · NDT · impact where specified |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Ring Type Joint Flange
RTJ flanges are used for high pressure and temperature — typically Class 600 and above, and on wellhead and API equipment. The metal ring deforms into the groove to seal.
- Groove to ASME B16.20 ring numbers
- Ring gasket softer than the groove material
- Groove hardness checked on order
More on choosing: Ring type joint flange guide.
ASTM A106 Gr B Ring Type Joint Flange: Why A106 B for ring type joint flanges
RTJ flanges are used for high pressure and temperature — typically Class 600 and above, and on wellhead and API equipment. The metal ring deforms into the groove to seal. In ASTM A106 Gr B, the choice usually comes down to the medium and temperature — the rows here are the points buyers check for this exact combination.
| Why this grade | Carbon and low-alloy flanges carry most utility, hydrocarbon and high-temperature service. ASTM A106 Gr B is picked for high-temperature process and steam piping in refineries and power plants. |
|---|---|
| Typical service | Refineries — Process and steam lines. |
| B16.5 material group | 1.1 |
| Bolting | ASTM A193 B7 studs with A194 2H nuts |
| Welding to carbon steel | Matching carbon or low-alloy filler is used; joints to stainless need ER309L |
| Matching filler | ER70S-6 / E7018 |
ASTM A106 Gr B Ring Type Joint Flange Chemical Composition
| Element | Weight % |
|---|---|
| Carbon | 0.30 max |
| Manganese | 0.29 – 1.06 |
| Silicon | 0.10 min |
| Phosphorus | 0.035 max |
| Sulphur | 0.035 max |
| Chromium | 0.40 max |
| Copper | 0.40 max |
| Nickel | 0.40 max |
ASTM A106 Gr B Ring Type Joint Flange Mechanical Properties
| Minimum values (elongation varies with wall) | Value |
|---|---|
| Tensile strength | 415 MPa · 60 ksi |
| Yield strength 0.2% | 240 MPa · 35 ksi |
| Elongation | 30% |
Full chemistry, properties and equivalents are on the ASTM A106 Gr B grade page.
Other ASTM A106 Gr B flanges
ASTM A106 Gr B Ring Type Joint Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiASTM A106 Gr B Ring Type Joint Flange dimensions — ASME B16.5 Class 150 & 300
Outside diameter, thickness and bolting are set by size and class. Values in mm; thickness excludes the 1.6 mm raised face.
| NPS | Cl 150 OD | Cl 150 thickness | Cl 150 bolt circle | Cl 150 bolts | Cl 300 OD | Cl 300 thickness | Cl 300 bolt circle | Cl 300 bolts |
|---|---|---|---|---|---|---|---|---|
| ½" | 90 | 9.6 | 60.3 | 4 × ½" | 95 | 12.7 | 66.7 | 4 × ½" |
| 1" | 110 | 12.7 | 79.4 | 4 × ½" | 125 | 15.9 | 88.9 | 4 × ⅝" |
| 1½" | 125 | 15.9 | 98.4 | 4 × ½" | 155 | 19.1 | 114.3 | 4 × ¾" |
| 2" | 150 | 17.5 | 120.7 | 4 × ⅝" | 165 | 20.7 | 127.0 | 8 × ⅝" |
| 3" | 190 | 22.3 | 152.4 | 4 × ⅝" | 210 | 27.0 | 168.3 | 8 × ¾" |
| 4" | 230 | 22.3 | 190.5 | 8 × ⅝" | 255 | 30.2 | 200.0 | 8 × ¾" |
| 6" | 280 | 23.9 | 241.3 | 8 × ¾" | 320 | 35.0 | 269.9 | 12 × ¾" |
| 8" | 345 | 27.0 | 298.5 | 8 × ¾" | 380 | 39.7 | 330.2 | 12 × ⅞" |
| 10" | 405 | 28.6 | 362.0 | 12 × ⅞" | 445 | 46.1 | 387.4 | 16 × 1" |
| 12" | 485 | 30.2 | 431.8 | 12 × ⅞" | 520 | 49.3 | 450.8 | 16 × 1⅛" |
Full chart: ASME B16.5 flange dimensions.
ASTM A106 Gr B Ring Type Joint Flange — questions buyers ask
Which ring gasket goes with an RTJ flange?
Oval or octagonal rings to ASME B16.20, in a material softer than the flange groove.
What pressure rating does a ASTM A106 Gr B ring type joint flange have?
It depends on class and temperature. ASTM A106 Gr B forgings are in ASME B16.5 material group 1.1; read your class column in that group's table at the design temperature.
Can ASTM A106 Gr B ring type joint flanges be welded to carbon steel?
Yes — matching carbon or low-alloy filler is used; joints to stainless need ER309L.
Which standard covers ASTM A106 Gr B ring type joint flanges?
The material is ASTM A105; dimensions follow ASME B16.5 · ASME B16.20. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a ASTM A106 Gr B ring type joint flange?
The steel price, the size and pressure class, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026