Stainless Steel 309S
AISI/SAE 309S · UNS S30908 · EN 1.4833, X12CrNi23-13 · JIS SUS309S · GB 06Cr23Ni13
309S is a high-chromium/high-nickel (about 23Cr-13Ni) heat-resistant austenitic stainless steel covered by UNS S30908, 1.4833, X12CrNi23-13 and SUS309S.
Values for the Solution Annealed condition
309S tempers and conditions
309S is supplied in 6 conditions, soft to hard. Solution Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
mill annealed / softened condition (bar, forging, tube) | General softened supply condition for bar, forgings and tube where full solution treatment is not separately certified. | 270 | 540 | 45 | 160 HB | 2.2 % IACS |
Hot Rolled, Annealed and Pickled plate (1D) | Most common heavy-plate form (3 mm and up) for furnace hearths, retorts and baffles. | 275 | 560 | 45 | 160 HB | 2.2 % IACS |
Solution AnnealedDefault 1050–1120 °C, rapid cool (ASTM A240 / EN 1.4833 plate & sheet) | Standard stocked condition for plate and sheet destined for high-temperature furnace and welded fabrication work. | 280 | 550 | 45 | 165 HB | — |
Cold Rolled, Annealed, Pickled and skin-passed sheet | Thin sheet (<3 mm) with a smoother 2B surface for fabricated liners, ducting and shielding. | 300 | 590 | 45 | 170 HB | 2.2 % IACS |
Cold Drawn bar / wire (as-drawn, not re-annealed) | Choose for small-diameter bar and fasteners needing higher strength and better surface/straightness than hot-finished bar. | 480 | 700 | 25 | 220 HB | — |
Quarter hard | Lightly cold-rolled strip where extra spring/stiffness is wanted and forming demands are modest. | 520 | 760 | 20 | 22 HRC | 2.2 % IACS |
What is 309S?
309S is a high-chromium/high-nickel (about 23Cr-13Ni) heat-resistant austenitic stainless steel covered by UNS S30908, 1.4833, X12CrNi23-13 and SUS309S. Engineers select it for scaling and oxidation resistance in continuous service to 1000 °C, and it is stocked as annealed and cold rolled 2B sheet, plate, hot rolled annealed and cold drawn bar. In the annealed condition it runs about 280 MPa yield, 550 MPa tensile, 45 % elongation and 165 HB (85 HRB); weldability is good (score 80) but machinability is low (38) and aqueous corrosion resistance (68) is not a substitute for a molybdenum grade. Long holds at 600–900 °C cause sigma-phase embrittlement; for hotter service move to 310S. 309S has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F). 309S has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 75% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
What is 309S used for?
- Welded furnace fittings
- Boiler baffles
- Heat-treatment fixtures and baskets
- Furnace muffles and liners
- Radiant tubes and burner parts
- Kiln and oven conveyor components
- Refractory anchors
Advantages
- High service temperature — 1,000°C (1,832 °F), better than 88% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
- Readily welded — 80/100, better than 80% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- Low strength — 280 MPa (40.6 ksi), worse than 75% of stainless steel grades
309S properties
Typical room-temperature values for 309S-Solution Annealed; bars are the position among stainless steel grades.
Physical3
309S has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
309S has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 75% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
309S is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 15.5 W/m·K (8.96 BTU/hr·ft·°F), better than 53% of stainless steel grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
309S conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of 309S takes about 62 MJ of energy and emits 4.6 kg of CO₂ — more than 75% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
309S's machinability is fair (38/100, better than 63% of stainless steel grades); weldability very good (80/100); formability good (62/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 309S is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 309S
Is 309S easy to machine?
Work-hardens rapidly — use rigid setups, positive-rake carbide, heavy constant feed, low-to-moderate speed and flood coolant; avoid dwell and re-cutting.
Can 309S be welded?
Readily welded by GTAW/GMAW/SMAW with 309/309L (or 310 for hottest service) filler; no preheat, keep interpass low and avoid long holds at 600–900 °C to limit sigma phase.
Can 309S be formed, bent or molded?
Cold forms like 304 but with higher force and springback; hot work at 1150–1200 °C and re-anneal at 1050–1120 °C with rapid cooling.
Manufacturability
The process limits FabDigit applies to 309S. Every 309S part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair38 / 100 |
|---|---|
| ISO material group | M.1 |
| Cutting speed (rough / finish) | 150 / 180 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better62 / 100 |
|---|---|
| Weldability | Excellent80 / 100 |
| Bendable | Yes |
309S chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CS30908; EN 1.4833 allows up to 0.15 % | ≤ 0.08 | 0.05 |
| SiEN 1.4833 up to 1.00 % | ≤ 0.75 | 0.5 |
| Mn | ≤ 2 | 1.3 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Cr | 22 – 24 | 23 |
| Ni | 12 – 15 | 13.5 |
| N | ≤ 0.1 | 0.05 |
| Fe | balance |
What surface finishes work on 309S?
Pickle and passivate after hot work or welding to restore the oxide film; can be ground, polished or electropolished — anodizing does not apply.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Organic Coating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 309S in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30908
- EN / DIN / Werkstoff-Nr.
- 1.4833X12CrNi23-13
- GB (China)
- 06Cr23Ni13
- JIS
- SUS309S
- Also called
- 0Cr23Ni13
- Similar grades
- 22Cr23Ni13
How much does 309S cost?
309S is a premium-cost stainless steel ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
309S — frequently asked
What is 309S used for?
309S is typically used for welded furnace fittings, boiler baffles, heat-treatment fixtures and baskets, furnace muffles and liners, radiant tubes and burner parts and kiln and oven conveyor components. In short: high-temp austenitic stainless.
What is the yield strength of 309S?
309S has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 75% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 309S easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Work-hardens rapidly — use rigid setups, positive-rake carbide, heavy constant feed, low-to-moderate speed and flood coolant; avoid dwell and re-cutting.
Can 309S be welded?
Yes — weldability is rated very good (80/100). Readily welded by GTAW/GMAW/SMAW with 309/309L (or 310 for hottest service) filler; no preheat, keep interpass low and avoid long holds at 600–900 °C to limit sigma phase.
What surface finishes work on 309S?
Pickle and passivate after hot work or welding to restore the oxide film; can be ground, polished or electropolished — anodizing does not apply.
Can 309S be formed, bent or molded?
Cold forms like 304 but with higher force and springback; hot work at 1150–1200 °C and re-anneal at 1050–1120 °C with rapid cooling.
What is the maximum service temperature of 309S?
309S is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 309S cost?
309S is a premium-cost stainless steel ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 309S?
Yes — 309S is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip (UNS S30908) — ASTM International (2023)
- EN 10095 / EN 10088-1 — Heat resisting steels and nickel alloys (X12CrNi23-13, 1.4833) — CEN (2018)
- JIS G 4304/G 4305 — Hot/Cold rolled stainless steel plate, sheet and strip (SUS309S) — JISC (2021)
- GB/T 4237 / GB/T 24511 — (06Cr23Ni13) — SAC (2015)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- Heat resistant stainless steel 4833/309S datasheet — Outokumpu (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.