Seamless TP309 Stainless Steel Pip e , known by designations such as UNS S30900, EN 1.4828, and 1.4833, is an austenitic chromium-nickel alloy renowned for its exceptional high-temperature resistance and corrosion performance. With a chromium content of 22.00-24.00% and nickel content of 12.00-15.00%, this alloy strikes a balance between oxidation resistance and mechanical strength, outperforming common 304 stainless steel in elevated-temperature applications.
Manufactured to rigorous standards including ASTM A213, ASTM A312, and GOST, TP309 seamless products undergo a precision production process to ensure uniform wall thickness and structural integrity. The alloy's unique composition makes it particularly suitable for environments where both high temperatures and corrosive media are present, offering reliable performance across diverse industrial sectors.
Zhejiang Xintongda Special Steel Manufacturing Co., Ltd. takes pride in delivering TP309 seamless pipes and tubes that meet the highest quality benchmarks, providing customers with durable solutions for their most demanding projects.
| Grade | C | Si | Mn | Cr | Ni | P | S | Mo |
| 309 | ≤0.20 | ≤1.00 | ≤2.00 | 22.00-24.00 | 12.00-15.00 | ≤0.045 | ≤0.03 | / |
| TP309S | ≤0.08 | ≤1.00 | ≤2.00 | 22.00-24.00 | 12.00-15.00 | ≤0.045 | ≤0.03 | ≤0.75 |
| TP309H | 0.04-0.10 | ≤1.00 | ≤2.00 | 22.00-24.00 | 12.00-15.00 | ≤0.045 | ≤0.03 | / |
| Grade | Tensile Strength (Ksi/MPa) | Yield Strength (Ksi/MPa) | Elongation (%) | Hardness (Brinell/Vickers) | Hardness (Rockwell) |
| TP309S | ≥75/515 | ≥30/205 | ≥35 | ≤192HBW/200HV | ≤90HRB |
| TP309H | ≥75/515 | ≥30/205 | ≥35 | ≤192HBW/200HV | ≤90HRB |
| Property | Value |
| Density | 7.93 g/cm³ |
| Melting Point | 1399-1454°C |
| Thermal Conductivity (100°C) | 15.9 W/m·K |
| Electrical Resistivity | 78.0 μΩ·cm |
| Coefficient of Thermal Expansion (20-100°C) | 16.0 μm/m·°C |
| Elastic Modulus | 193 GPa |
Outer Diameter Range: 6-1016 mm
Wall Thickness Range: 1-65 mm
Custom lengths available upon request
TP309 exhibits remarkable oxidation resistance up to 1038°C (1900°F) under non-cyclic conditions, making it ideal for continuous high-temperature service. Its high chromium and nickel content forms a stable oxide layer, protecting the alloy from scaling and degradation in furnace environments, flue gas systems, and other heat-intensive applications.
Sulfur-Containing Atmospheres: The alloy’s lower nickel content enhances resistance to sulfur attack, allowing use in sulfurous environments up to 1000°C (1832°F).
General Corrosion: TP309 offers superior corrosion resistance compared to 304 stainless steel in oxidizing media, such as dilute acids and atmospheric conditions.
Alkaline & Neutral Solutions: It shows good resistance to most alkaline and neutral salt solutions, making it suitable for food processing and chemical handling.
TP309 maintains significant room-temperature strength even at high temperatures, with a minimum tensile strength of 515 MPa. This property ensures structural integrity in components subjected to thermal stress, such as boiler parts and exhaust systems.
The austenitic structure of TP309 allows easy welding using standard techniques (TIG, MIG, stick welding). It supports cold forming and machining, though work hardening may occur during fabrication. Post-weld annealing is recommended for critical applications to optimize ductility and corrosion resistance.
While renowned for high-temperature performance, TP309 also demonstrates stable mechanical properties in cryogenic environments, making it suitable for applications that require resistance to both extreme heat and cold.
Superheater and reheater tubes in power plant boilers
Heat exchanger components in industrial processes
Steam pipelines and headers requiring high-temperature durability
Piping and ductwork for removing sulfur dioxide from flue gases
Components in wet and dry FGD systems exposed to corrosive byproducts
Stack liners and scrubber parts in power generation facilities
Furnace burners, retorts, and radiant tubes
Conveyor belts and trays for heat-treating processes
Incinerator components subjected to high-temperature gases
Exhaust manifolds and pipes in high-performance vehicles
Aircraft engine exhaust components
Aftertreatment systems for diesel engines
Reactors and vessels for handling oxidizing chemicals
Piping in sulfuric acid production and other corrosive processes
Heat exchangers in refinery applications
High-temperature processing equipment for food sterilization
Steam pipes and cookers in commercial kitchens
Hygienic tubing for pharmaceutical manufacturing
TP309: Standard grade with ≤0.20% carbon, suitable for general high-temperature use.
TP309S: Low-carbon variant (≤0.08% C) to minimize carbide precipitation during welding, ideal for corrosion-sensitive applications.
TP309H: High-carbon grade (0.04-0.10% C) for enhanced strength at elevated temperatures, suitable for long-term high-heat service.
No, TP309 exhibits only moderate resistance to carbon absorption and is not recommended for highly carburizing atmospheres. For such applications, alloys with higher chromium content or specific carburization resistance should be considered.
TP309 can withstand continuous service up to 1038°C (1900°F) under non-cyclic conditions. In sulfur-containing atmospheres, the maximum temperature is reduced to 1000°C (1832°F) to maintain corrosion resistance.
Like other austenitic stainless steels, TP309 is non-magnetic in its annealed condition. Cold working may induce slight magnetism due to martensitic transformation, but it remains primarily non-magnetic.
TP309 has a higher chromium (22-24%) and nickel (12-15%) content than 304 (18-20% Cr, 8-10.5% Ni), offering superior high-temperature oxidation resistance and strength. While 304 is suitable for general corrosion resistance, TP309 excels in elevated-temperature applications.
Use 309L or 310 stainless steel filler metals to match the alloy’s composition. Control heat input to avoid excessive grain growth, and consider post-weld annealing for critical components to restore optimal properties.
Standard pickling or bright annealing is sufficient for most applications. Polishing can be applied for aesthetic purposes or to enhance corrosion resistance in hygienic environments like food processing.
Standard mill test certificates are included, and 3.2 Certification is available upon request to meet specific industry standards such as ASTM or GOST.
