309S Stainless Steel Round Bar (UNS S30908)
309S Stainless Steel Round Bar (UNS S30908) is a low-carbon, high-chromium austenitic stainless steel engineered for high-temperature and oxidation-resistant applications. The reduced carbon content compared to standard 309 minimizes carbide precipitation during welding, making 309S round bars highly suitable for fabricated and welded components exposed to elevated temperatures and corrosive atmospheres.
Key Features
- Excellent oxidation and scaling resistance at elevated temperatures
- Low carbon content improves weldability and reduces intergranular corrosion
- High chromium and nickel content for superior heat resistance
- Good strength and toughness at high operating temperatures
- Resistant to sulfidation and carburization environments
- Non-magnetic in annealed condition
Specification
| Parameter | Details |
|---|---|
| Product Type | Round Bar |
| Material Grade | Stainless Steel 309S |
| UNS Number | S30908 |
| Standards | ASTM A276, ASTM A479, ASME SA276, SA479 |
| Manufacturing Process | Hot Rolled / Cold Drawn |
| Heat Treatment | Annealed |
| Surface Finish | Black, Bright, Polished, Peeled, Turned |
Equivalent Grades of 309S Round Bar
| Standard | Equivalent Grade |
|---|---|
| ASTM / ASME | 309S |
| UNS | S30908 |
| EN | 1.4833 |
| DIN | X10CrNiSi25-21 |
| JIS | SUS 309S |
Sizes
| Diameter | Length |
|---|---|
| 3 mm – 500 mm | Random Length / Cut Length / Up to 6 meters |
| Custom Sizes | Available on request |
309S Chemical Composition
| Element | Percentage (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Chromium (Cr) | 22.00 – 24.00 |
| Nickel (Ni) | 12.00 – 15.00 |
| Manganese (Mn) | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Iron (Fe) | Balance |
UNS S30908 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 217 HB |
309S Physical Properties
| Property | Value |
|---|---|
| Density | 7.9 g/cm³ |
| Melting Range | 1399 – 1454°C |
| Thermal Conductivity | 14.2 W/m·K |
| Electrical Resistivity | 0.78 µΩ·m |
| Modulus of Elasticity | 193 GPa |
Types of 309S Stainless Steel Round Bar
- Hot Rolled Round Bar
- Cold Drawn Round Bar
- Bright Stainless Steel Bar
- Polished Round Bar
- Forged Round Bar
Applications
- Furnace parts and heat-treatment equipment
- Petrochemical and refinery components
- Heat exchangers and boiler parts
- Power generation and thermal processing systems
- Kilns, burners, and combustion chambers
- High-temperature welded structural components
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