SS 304L Expander FlangeASTM A182 · ASME B16.5 (flange end) · Manufacturer, stockist & exporter, India
AISI 304L · UNS S30403 · EXP
An SS 304L expander flange is a weld neck flange whose hub increases the pipe size, made from SS 304L to ASTM A182 F304L. 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 A182
- 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 SS 304L Expander Flange?
- What it is
- A weld neck flange whose hub increases the pipe size
- Material
- ASTM A182 F304L
- Dimensions
- ASME B16.5 (flange end)
- Grade
- SS 304L · UNS S30403
- Best at
- Welded tanks, piping and vessels in general corrosive service
SS 304L Expander Flange Specification
| Product | SS 304L Expander Flange |
|---|---|
| Material standard | ASTM A182 F304L |
| 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 | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
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.
SS 304L Expander Flange: Why 304L 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 SS 304L, 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 | Stainless flanges are chosen where carbon steel would rust or contaminate the process. SS 304L is picked for welded tanks, piping and vessels in general corrosive service. |
|---|---|
| Typical service | Process piping — Welded lines in chemical and pharma plants. |
| B16.5 material group | 2.3 |
| Bolting | ASTM A193 B8 studs with A194 8 nuts |
| Welding to carbon steel | ER309L (or E309L electrode) is the usual filler when joining it to carbon steel |
| Matching filler | ER308L (AWS A5.9) |
SS 304L Expander Flange Chemical Composition
| Element | Weight % |
|---|---|
| Chromium | 17.5 – 19.5 |
| Nickel | 8.0 – 12.0 |
| Carbon | 0.030 max |
| Manganese | 2.00 max |
| Silicon | 0.75 max |
| Nitrogen | 0.10 max |
| Phosphorus | 0.045 max |
| Sulphur | 0.030 max |
SS 304L Expander Flange Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 485 MPa · 70 ksi |
| Yield strength 0.2% | 170 MPa · 25 ksi |
| Elongation | 40% |
| Hardness | 201 HB max |
Full chemistry, properties and equivalents are on the SS 304L grade page.
Other SS 304L flanges
SS 304L Expander Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 304L 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 SS 304L expander flange have?
It depends on class and temperature. SS 304L forgings are in ASME B16.5 material group 2.3; read your class column in that group's table at the design temperature.
Can SS 304L expander flanges be welded to carbon steel?
Yes — ER309L (or E309L electrode) is the usual filler when joining it to carbon steel.
Which standard covers SS 304L expander flanges?
The material is ASTM A182 F304L; 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 SS 304L expander flange?
The alloy 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