309 stainless steel is an austenitic chromium-nickel alloy specifically engineered for high-temperature service up to 1093°C (2000°F). With elevated chromium (23%) and nickel (14%) content compared to 304, it offers superior oxidation resistance and retains high tensile and creep strength at elevated temperatures. This grade is classified as a true heat-resisting alloy, widely used for industrial furnace components, boiler baffles, radiant tubes, and heat treatment fixtures .
1. Product Specifications & Physical DataZYTC Alloy supplies 309 stainless steel in comprehensive mill forms for high-temperature industrial applications requiring verified heat resistance and mechanical properties. Available Forms: Coil, strip, wire, sheet, plate, bar, and custom configurations . Specifications: ASTM A240, ASTM A276, ASTM A312, EN 10088-2 1.4828, UNS S30900 .
| Chemical Composition (Weight %) | 309 Stainless Specification |
|---|
| Chromium (Cr) | 22.0 - 24.0 | | Nickel (Ni) | 12.0 - 15.0 | | Carbon (C) | 0.20 max. | | Manganese (Mn) | 2.0 max. | | Silicon (Si) | 1.0 max. | | Phosphorus (P) | 0.045 max. | | Sulfur (S) | 0.030 max. | | Iron (Fe) | Balance |
| Physical Properties | Metric | Imperial |
|---|
| Density | 8.0 g/cm³ | 0.289 lb/in³ | | Melting Point | 1400 - 1455°C | 2550 - 2650°F | | Modulus of Elasticity | 200 GPa | 29,000 ksi | | Poisson's Ratio | 0.27 - 0.30 | 0.27 - 0.30 | | Shear Modulus | 77 GPa | 11,200 ksi | | Thermal Conductivity (RT) | 15.6 W/m·K | 108 BTU·in/hr·ft²·°F |
| Mechanical Properties (Minimum) | Value | Unit |
|---|
| Tensile Strength | 620 MPa | 90 ksi | | Yield Strength (0.2% offset) | 310 MPa | 45 ksi | | Elongation (in 50mm) | 45% | 45% | | Hardness (Brinell) | 147 max. | 147 max. | | Izod Impact | 120-165 J | 88.5-122 ft·lbf |
2. Fabrication & Material ComparisonHeat Treatment: Solution anneal 1038-1121°C (1900-2050°F), rapid cool (water quench or accelerated air cool) . Hot Working: Hot work at 1177°C (2150°F); reheat and rapid quench refine grain structure . Cold Working: Drawing, stamping, and forming possible but require intermediate annealing due to rapid work hardening . Machining: Machinability similar to 304; requires sharp tools, rigid setups, and powerful coolant to manage work hardening . Welding: Good weldability using fusion and resistance methods; oxyacetylene not recommended due to carbon pickup; 309 filler recommended . Material Comparison: vs. 304 Stainless: Higher chromium and nickel provide superior high-temperature strength and oxidation resistance . vs. 310 Stainless: Lower nickel (14% vs. 20%) and chromium (23% vs. 25%) than 310; more cost-effective for many high-temperature applications . vs. 309S (Low Carbon): Lower carbon version (0.08% max) for improved weldability and intergranular corrosion resistance . vs. 330 Stainless: Lower nickel than 330 (14% vs. 34-37%); 309 offers good performance at lower cost .
3. ApplicationsIndustrial Furnaces: Linings, radiant tubes, baffles, firebox sheets, heat treatment fixtures Boiler Components: Boiler baffles, superheater supports, combustion chambers Ovens & Conveyors: Oven linings, conveyor belts, high-temperature containers Heat Treating Equipment: Annealing covers, retorts, baskets, trays Petrochemical: Catalyst grid supports, reactor internals, high-temperature piping Cement & Lime: Kiln components, preheater parts
Contact ZYTC Alloy for certified 309 stainless steel materials with complete traceability, ASTM/EN specifications, technical datasheets, and competitive pricing on standard sizes or custom-fabricated components. Email: daisy@zytcsteel.com WhatsApp/WeChat: +86 17335753350 |
