309S Buttweld Pipe Fittings
ASTM A403 WP309S / EN 1.4833 (X12CrNi23-13) — 23Cr-13Ni heat-resistant austenitic stainless steel for oxidation resistance in continuous service to ~1095°C. Furnace and kiln components, heat-treatment fixtures, and the standard grade for dissimilar-metal and clad welding. EN 10253-2 Type B and ASME B16.9. EN 10204 3.1 standard; 3.2 TPI on request.
½″–48″
Size Range
~1095°C
Max Continuous
23Cr-13Ni
Composition
EN 10204
3.1 Std / 3.2 On Req.
Request 309S Quote
Response within 1 business day
309S Grade Equivalents
| ASTM | EN W.Nr. | EN Name | UNS | ASME P-No. |
|---|---|---|---|---|
| A403 WP309S (fittings) | 1.4833 | X12CrNi23-13 | S30908 | 8, Gr 3 |
| A182 F310 / 309 (flanges) | 1.4833 | X12CrNi23-13 | S30908 | 8 |
| A312 TP309S (pipe) | 1.4833 | X12CrNi23-13 | S30908 | 8 |
| A240 309S (plate) | 1.4833 | X12CrNi23-13 | S30908 | 8 |
Chemical Composition — 309S / 1.4833
| Standard | C | Cr | Ni | Mn | Si | P | S |
|---|---|---|---|---|---|---|---|
| ASTM A403 WP309S | ≤0.08 | 22.0–24.0 | 12.0–15.0 | ≤2.0 | ≤1.0 | ≤0.045 | ≤0.030 |
| EN 1.4833 (X12CrNi23-13) | ≤0.15 | 22.0–24.0 | 12.0–14.0 | ≤2.0 | ≤1.0 | ≤0.045 | ≤0.015 |
EN 1.4833 is the nearest heat-resistant equivalent and permits higher carbon (≤0.15%) for creep strength; ASTM WP309S is the low-carbon variant (C ≤0.08%) preferred for welded fittings. Both are the 23Cr-13Ni heat-resistant grade with no molybdenum.
Mechanical Properties — 309S / 1.4833
| Standard | Min. UTS (MPa) | Min. YS (MPa) | Elongation (%) | Max. Hardness | HT Condition |
|---|---|---|---|---|---|
| ASTM A403 WP309S | 515 | 205 | ≥35% | 217 HBW | Solution annealed |
| EN 1.4833 (EN 10253-2) | 500–700 | ≥210 | ≥30% | 223 HBW | Solution annealed |
High-Temperature Service & Welding
✓ No PWHT Required — supplied solution annealed.
309S (ASTM A403 WP309S / EN 1.4833) is austenitic and does not require post-weld heat treatment. It is delivered solution annealed and does not undergo martensitic transformation during welding.
Oxidation, Dissimilar Welding & Guidance
- Oxidation resistance: continuous service to ~1095°C; slightly lower than 310S but sufficient for many furnace duties.
- Dissimilar & clad welding: 309/309L is the standard filler and buffer layer for joining carbon or low-alloy steel to stainless, and for the first pass on stainless-clad steel.
- Filler metal: ER309 / ER309L (GTAW / TIG) or E309-16 (SMAW).
- ASME P-No.: 8, Group 3. Weld procedure qualification per ASME IX or ISO 15614-1.
⚠ Sigma Phase & Wet Service
Prolonged exposure in the 600–900°C range can precipitate sigma phase, reducing room-temperature ductility. 309S is a heat-resistant grade with no molybdenum and is not suited to aqueous chloride or acid service; for wet corrosion select 316L, 317L, duplex or a nickel alloy. Contact our technical team to confirm material selection.
309S Fitting Types Available
90° Elbow (LR & SR)
Long Radius & Short Radius
ASME B16.9
45° Elbow
Long Radius
ASME B16.9
Equal Tee
Straight tee, equal branch
ASME B16.9
Reducing Tee
Reduced branch outlet
ASME B16.9
Concentric Reducer
Inline bore reduction
ASME B16.9
Eccentric Reducer
Flat bottom / top configurations
ASME B16.9
End Cap
Pipe end closure
ASME B16.9
Stub End (Lap Joint)
For use with lap joint flanges
ASME B16.9
Cross / Lateral
Four-way and angled branch
ASME B16.9
309S vs 310S — Heat-Resistant Grades
| Property | 309S (WP309S / 1.4833) | 310S (WP310S / 1.4845) |
|---|---|---|
| Chromium | 22.0–24.0% | 24.0–26.0% |
| Nickel | 12.0–15.0% | 19.0–22.0% |
| Max continuous service | ~1095°C | ~1150°C |
| Distinctive use | Dissimilar / clad welding | Highest-temperature furnace |
Ready to order 309S heat-resistant fittings?
Specify size, schedule, fitting type, standard (ASME B16.9 or EN 10253-2 Type B), and required MTR (EN 10204 3.1 or 3.2). We respond within 1 business day.
Request a Quote →