ASTM A106 Gr B Expander FlangeASTM A105 · ASME B16.5 (flange end) · Manufacturer, trader & exporter, India
SA-106 Gr B · Seamless carbon steel pipe · EXP
An ASTM A106 Gr B expander flange is a weld neck flange whose hub increases the pipe size, for use with ASTM A106 Gr B pipe. ASTM A106 Gr B itself is a pipe or plate specification, so the matching expander flange is made to ASTM A105 — which is what we supply for A106 B lines. Expander flanges step up the line size at a pump or valve outlet, replacing a reducer and a standard weld neck flange with one part.
- ASTM A105
- ASME B16.5 (flange end)
- 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 Expander Flange?
- What it is
- A weld neck flange whose hub increases the pipe size
- Material
- ASTM A105
- Dimensions
- ASME B16.5 (flange end)
- Grade
- ASTM A106 Gr B
- Best at
- High-temperature process and steam piping in refineries and power plants
ASTM A106 Gr B Expander Flange Specification
| Product | ASTM A106 Gr B Expander Flange |
|---|---|
| Material standard | ASTM A105 |
| Dimensional standard | ASME B16.5 (flange end) |
| 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 or 3.2 on request / as specified in the PO |
When to Choose an Expander Flange
Expander flanges step up the line size at a pump or valve outlet, replacing a reducer and a standard weld neck flange with one part.
- Increases one or two pipe sizes
- Saves a weld and space
- Weld neck design
More on choosing: Expander flange guide.
ASTM A106 Gr B Expander Flange: Why A106 B for expander flanges
Expander flanges step up the line size at a pump or valve outlet, replacing a reducer and a standard weld neck flange with one part. 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 Expander Flange Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Phosphorus | As specified |
| Sulphur | As specified |
| Chromium | As specified |
| Copper | As specified |
| Nickel | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A106 Grade B.
ASTM A106 Gr B Expander Flange Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM A106 Grade B — condition per order.
Full chemistry, properties and equivalents are on the ASTM A106 Gr B grade page.
Other ASTM A106 Gr B flanges
ASTM A106 Gr B Expander Flange — questions buyers ask
When is an expander flange used?
Most often at pump and valve outlets where the line size increases immediately.
What pressure rating does a ASTM A106 Gr B expander 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 expander 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 expander flanges?
The material is ASTM A105; dimensions follow ASME B16.5 (flange end). 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 expander 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 or 3.2 certificates available on request / as specified in the PO; dimensional reports as required. PMI can be arranged depending on product and requirements, as specified in the PO.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026