SS 904L Expander FlangeASTM A182 · ASME B16.5 (flange end) · Manufacturer, stockist & exporter, India
Alloy 904L · UNS N08904 · EXP
An SS 904L expander flange is a weld neck flange whose hub increases the pipe size, made from SS 904L to ASTM A182 F904L. 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 904L Expander Flange?
- What it is
- A weld neck flange whose hub increases the pipe size
- Material
- ASTM A182 F904L
- Dimensions
- ASME B16.5 (flange end)
- Grade
- SS 904L · UNS N08904
- Best at
- Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water
SS 904L Expander Flange Specification
| Product | SS 904L Expander Flange |
|---|---|
| Material standard | ASTM A182 F904L |
| 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 904L Expander Flange: Why 904L 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 904L, 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 904L is picked for dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water. |
|---|---|
| Typical service | Sulphuric acid plants — Coolers, piping and tanks for dilute sulphuric acid. |
| Bolting | as the project specifies |
| Welding to carbon steel | ER309L (or E309L electrode) is the usual filler when joining it to carbon steel |
| Matching filler | ER385 (AWS A5.9) |
SS 904L Expander Flange Chemical Composition
| Element | Weight % |
|---|---|
| Nickel | 23.0 – 28.0 |
| Chromium | 19.0 – 23.0 |
| Molybdenum | 4.0 – 5.0 |
| Copper | 1.0 – 2.0 |
| Carbon | 0.020 max |
| Manganese | 2.00 max |
| Silicon | 1.00 max |
| Nitrogen | 0.10 max |
SS 904L Expander Flange Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 490 MPa · 71 ksi |
| Yield strength 0.2% | 220 MPa · 31 ksi |
| Elongation | 35% |
| Hardness | 90 HRB max |
Full chemistry, properties and equivalents are on the SS 904L grade page.
Other SS 904L flanges
SS 904L Expander Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 904L Expander Flange — questions buyers ask
When is an expander flange used?
Most often at pump and valve outlets where the line size increases immediately.
Can SS 904L 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 904L expander flanges?
The material is ASTM A182 F904L; 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 904L 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