Stainless 309S · UNS S30908 · W. Nr. 1.4833
Stainless 309S (S30908): composition, properties, fittings and flanges
Stainless 309S (S30908, W. Nr. 1.4833) is High-chromium high-nickel heat-resistant austenitic stainless steel. Stainless 309S is specified at Chromium 22.0 - 24.0, Nickel 12.0 - 15.0. 309S roughly doubles the chromium and nickel of 304, giving oxidation resistance to about 1000 °C plus the thermal expansion headroom needed for…
- UNS
- S30908
- W. Nr.
- 1.4833
- Density
- 8.00 g/cm³ (0.289 lb/in³)
- Key strength
- 515 MPa / 75 ksi
Identification and standards
| Short form | Stainless 309S · UNS S30908 · W. Nr. 1.4833 |
|---|---|
| Classification | High-chromium high-nickel heat-resistant austenitic stainless steel |
| UNS | S30908 |
| Werkstoff number | 1.4833 |
| Material family | Stainless Steel |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Chromium (Cr) | 22.0 - 24.0 | Oxidation and scaling resistance |
| Nickel (Ni) | 12.0 - 15.0 | Austenite stability and thermal fatigue |
| Carbon (C) | 0.08 max | - |
| Manganese (Mn) | 2.00 max | - |
| Silicon (Si) | 0.75 max | - |
| Phosphorus (P) | 0.045 max | - |
| Sulphur (S) | 0.030 max | - |
| Iron (Fe) | Balance | Matrix |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed) | 515 MPa / 75 ksi |
|---|---|
| 0.2 % yield strength, min | 205 MPa / 30 ksi |
| Elongation in 2 in, min | 40 % |
| Typical hardness, annealed | 145 - 190 HB |
| Useful continuous service temperature | About 1000 °C |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.00 g/cm³ (0.289 lb/in³) |
|---|---|
| Melting range | 1400 - 1455 °C (2550 - 2650 °F) |
| Modulus of elasticity | 200 GPa (29.0 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 15.6 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 15.0 µm/m·°C |
| Specific heat capacity | 500 J/kg·K |
Specifications by product form
| Forgings & flanges | ASTM A182 F309S family · ASME SA-182 |
|---|---|
| Butt weld fittings | ASTM A403 WP309S · ASME SA-403 |
| Seamless pipe & tube | ASTM A312 TP309S · ASME SA-312 |
| Plate / sheet / strip | ASTM A240 309S · ASME SA-240 |
| Bar / rod | ASTM A276 / A479 |
| Welding consumables | ER309 / ER309L |
| UNS / EN / China | UNS S30908 · W. Nr. 1.4833 · GB 06Cr23Ni13 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- Furnace parts, kiln liners and heat treatment fixtures
- Transition joints and buttering layers on carbon steel
- Waste incineration and boiler components
- Exhaust manifolds and thermal oxidiser ducting
Welding, forming and machining
- Welding
- Weld with ER309L filler, which is also the standard choice for joining stainless to carbon steel because it tolerates iron dilution.
- Heat treatment
- Solution anneal at 1040 - 1120 °C and water quench.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Stainless 309S from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.