SS 304 Pipe FittingsASTM A403 WP304 · Manufacturer, stockist & exporter, India
Also sold as AISI 304 · UNS S30400 · W.Nr 1.4301 · 18/8 stainless
SS 304 pipe fittings are made to ASTM A403 WP304 for buttweld fittings and ASTM A182 F304 for forged socket-weld and threaded fittings, with dimensions to ASME B16.9 and B16.11. It is a austenitic chromium-nickel stainless steel, chosen for general corrosion resistance, food, water and architectural work. Kanak Steel & Engineering Co. supplies it with EN 10204 3.1 mill certificates from Mumbai to buyers across India, the Gulf, South-East Asia, South America, Europe, the UK and the USA.
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is SS 304 Pipe Fittings?
SS 304 pipe fittings is an austenitic chromium-nickel stainless steel supplied as pipe fittings to ASTM A403 WP304 (UNS S30400). Buyers specify it for general corrosion resistance, food, water and architectural work. It is also sold as AISI 304, UNS S30400, W.Nr 1.4301.
- What it is
- Austenitic chromium-nickel stainless steel
- Buttweld
- ASTM A403 WP304
- Forged
- ASTM A182 F304
- Dimensions
- ASME B16.9 · B16.11 · MSS SP-43
- Sizes
- Buttweld ½" – 48" · forged ⅛" – 4"
- Best at
- General corrosion resistance, food, water and architectural work
SS 304 Pipe Fittings Specification & Sizes
| Buttweld fittings | ASTM A403 WP304 — dimensions to ASME B16.9, MSS SP-43 |
|---|---|
| Forged fittings | ASTM A182 F304 — dimensions to ASME B16.11 |
| MSS SP-43 light-wall fittings | ASTM A403 CR304 — the A403 CR grade for MSS SP-43 dimensions (no class suffix) |
| Short-radius elbows | ASME B16.9 (formerly B16.28) |
| Buttweld sizes | NPS ½" to 48", schedule to match the pipe |
| Forged classes | Socket weld 3000 / 6000 / 9000 · threaded 2000 / 3000 / 6000 |
| Types | Elbow · Tee · Reducer · Cap · Stub end · Cross · Bend · Lateral · Coupling · Union · Nipple · Plug |
| Testing | PMI · dimensional · radiography of welded fittings · IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
Choosing SS 304 Fittings: Elbow Radius, Schedule & Class
ASTM A403 fittings come in classes: S seamless, W welded (welds radiographed or ultrasonically examined), WX all welds radiographed, WU all welds ultrasonically tested. Write the class after the grade, e.g. WP304-S.
Radius (LR, SR, 3D), the schedule-to-class map and the 1.5 mm socket-weld gap are explained in the fittings guide. For 304, buttweld fittings are ASTM A403 WP304 and forged fittings ASTM A182 F304.
SS 304 Pipe Fittings Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Chromium | As specified |
| Nickel | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Nitrogen | As specified |
| Phosphorus | As specified |
| Sulphur | As specified |
| Iron | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A240 for UNS S30400.
SS 304 Pipe Fittings Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
| Hardness | 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 A240 for UNS S30400 — Annealed plate & sheet.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8 g/cm³ |
| Melting range | 1400 – 1450 °C |
| Magnetic | Non-magnetic annealed; slightly magnetic after cold work |
| PREN (approx.) | ≈ 18 |
SS 304 Equivalent Grades
SS 304 buttweld fitting dimensions — ASME B16.9
Centre-to-end and end-to-end dimensions are the same for every alloy; the wall thickness follows the pipe schedule. Values in mm.
| NPS | OD | 90° LR elbow A | 45° elbow B | Tee C | Reducer H | Cap E |
|---|---|---|---|---|---|---|
| ½" | 21.3 | 38 | 16 | 25 | — | 25 |
| 1" | 33.4 | 38 | 22 | 38 | 51 | 38 |
| 1½" | 48.3 | 57 | 29 | 57 | 64 | 38 |
| 2" | 60.3 | 76 | 35 | 64 | 76 | 38 |
| 3" | 88.9 | 114 | 51 | 86 | 89 | 51 |
| 4" | 114.3 | 152 | 64 | 105 | 102 | 64 |
| 6" | 168.3 | 229 | 95 | 143 | 140 | 89 |
| 8" | 219.1 | 305 | 127 | 178 | 152 | 102 |
| 10" | 273.1 | 381 | 159 | 216 | 178 | 127 |
| 12" | 323.9 | 457 | 190 | 254 | 203 | 152 |
Full chart to 24": ASME B16.9 fitting dimensions.
Six-digit Harmonized System heading (iron and steel, chapter 72–73). Your country adds its own digits — confirm with your customs broker. All HS codes.
How to Verify SS 304 Pipe Fittings with PMI
Positive material identification with a handheld XRF gun confirms the alloy on the piece itself, in seconds, before it is cut or welded. SS 304 is most often mixed up with SS 316 / 316L — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen; those come from the mill certificate or optical emission (OES) testing. PMI can be arranged on request — state it on your enquiry.
Under technical review for TDS.
| Element | SS 304 | SS 316 / 316L |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | — | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
SS 304 Pipe Fittings Price — What Decides It
Two quotes for "304 pipe fittings" can differ by 20% and both be fair. We quote 304 pipe fittings per kg for full sizes and per piece for cut sizes. These six things move the price per kg, so you can compare offers like for like.
SS 304 pipe fittings by type
SS 304 Pipe Fittings Applications
SS 304 is specified when the cheaper grade will not survive the service but a higher alloy would be more than the job needs. These are the jobs our buyers use it for.
SS 304 Pipe Fittings vs 316L, 304L and 904L
| Grade | Pipe Fittings standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| SS 304L | ASTM A403 WP304L | ≈ 18 | Welded tanks, piping and vessels in general corrosive service |
| SS 304 | ASTM A403 WP304 | ≈ 18 | General corrosion resistance, food, water and architectural work |
| SS 316 / 316L | ASTM A403 WP316L | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| SS 904L | ASTM A403 WP904L | ≈ 35 | Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
SS 304 Corrosion Resistance — Element by Element
Each alloying addition has a job. Knowing which one protects against your medium is the quickest way to judge whether 304 fits.
About 18% chromium forms the passive film that makes the steel stainless.
Nickel keeps the structure austenitic — tough at low temperature and easy to form and weld.
Standard carbon level: fine for most work, but choose 304L where heavy sections are welded and service is corrosive.
Without molybdenum, 304 pits in chlorides — step up to 316L for coastal or salty service.
How your 304 pipe fittings order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked against your order; PMI before processing is available on request.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked.
- 04Inspection — your third-party inspector witnesses, or we share photos and test reports.
- 05Packing & dispatch — seaworthy packing from Nhava Sheva (JNPT), Mumbai, FOB or CIF, documents sent before the vessel sails.
Standards on this page
Welding & Fabricating SS 304 Pipe Fittings
SS 304 welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ER308 / ER308L (AWS A5.9) |
|---|---|
| Over-alloyed filler | ER309L for dissimilar joints to carbon steel |
| Preheat | Not required; keep interpass temperature low |
| Cutting | Thermal or abrasive cutting; grind off heat-tinted edges before welding |
Follow your approved WPS; this is general guidance. See also 304 fittings and 304 flanges for the matching pipe-system parts.
How to Order SS 304 Pipe Fittings: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Fitting type, size and schedule / class
- Buttweld, socket weld or threaded
- Seamless or welded (buttweld fittings)
- Material standard and grade marking
- Certificate type and extra tests
- Delivery port, Incoterm and required date
SS 304 pipe fittings for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 304 pipe fittings — questions buyers ask
Is SS 304 the same as AISI 304?
AISI 304, UNS S30400, W.Nr 1.4301 are names used for SS 304 (W.Nr / EN numbers and older UNS variants are the closest designations; their limits can differ slightly, so specify the UNS number and ASTM grade on the order), and pipe fittings is ordered to ASTM A403 WP304 whichever name is on the enquiry.
Which standard covers SS 304 buttweld fittings?
ASTM A403 WP304 is the material specification; dimensions follow ASME B16.9 (light-wall MSS SP-43 fittings are ordered as CR304). Forged socket-weld and threaded fittings are made from ASTM A182 F304 material to ASME B16.11.
What is the difference between SS 304 WP-S and WP-W fittings?
S is seamless; W is welded from plate or welded pipe, with the welds examined by radiography or ultrasonics. WX means all welds radiographed and WU all welds ultrasonically tested. Seamless costs more and is preferred for critical service.
Can SS 304 fittings be welded to carbon steel?
Yes — ER309L (or E309L electrode) is the usual filler when joining it to carbon steel.
SS 304 or SS 904L — which should I choose?
SS 304 is chosen for general corrosion resistance, food, water and architectural work. SS 904L is the step up when you need more pitting resistance or strength. See the comparison table on this page, or ask us with your process conditions.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026