What is ASTM A312 TP309 Seamless Pipes?
ASTM A312 TP309 seamless pipes are manufactured from chromium-nickel stainless steel
containing higher chromium (22–24%) and nickel (12–15%) compared to 304 grade. This
provides superior resistance to oxidation and scaling at high temperatures up to
approximately 1093°C.
These pipes are supplied in seamless form for critical pressure and high-temperature applications.
ASTM A312 TP309 Seamless Pipe Specifications
| Product Type : | Stainless Steel Pipe |
| Grade : | TP309 |
| Manufacturing Type : | Seamless |
| Pipe Size Range : | 1/8″ NB to 24″ NB |
| Schedules | 5S, 10S, 40S, 80S, 160, XS, XXS |
| Length | 6m, 12m, Custom Cut |
| End Type | Plain End, Beveled End |
| Testing | Hydrostatic Test, PMI, UT, NDT |
| Certification | EN 10204 3.1 / 3.2 MTC |
All specifications are in accordance of ASTM A312 / ASME SA312 standards. Mechanical and chemical values are as per standard limits. Mill Test Certificates (MTC) available upon request.
Chemical Composition of SS 309 Seamless Pipes (ASTM A312 TP309)
| Element | Max (%) |
|---|---|
| Carbon (C) | 0.20 |
| Manganese (Mn) | 2.00 |
| Phosphorus (P) | 0.045 |
| Sulfur (S) | 0.030 |
| Silicon (Si) | 1.00 |
| Chromium (Cr) | 22.0 - 24.0 |
| Nickel (Ni) | 12.0 - 15.0 |
| Iron (Fe) | Balance |
Higher chromium content provides superior oxidation resistance compared to SS 304 and 310 in certain conditions.
Mechanical Properties of ASTM A312 TP309 Seamless Pipe
| Property | Minimum Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa |
| Elongation | ≥ 35% |
Values apply in annealed condition as per ASTM standards.
High Temperature Performance – ASTM A312 TP309
ASTM A312 TP309 Seamless Pipes are engineered for elevated temperature service. The higher chromium (22–24%) and nickel (12–15%) content provides superior oxidation resistance and thermal stability.
Commonly used in furnaces, heat exchangers, petrochemical plants, boilers, and refinery piping systems.
Applications of ASTM A312 TP309 Stainless Steel Pipes
- SS 309 seamless pipes are widely used in:
- 🔸Furnace parts and heat exchangers
- 🔸Petrochemical processing plants
- 🔸Oil & gas refineries
- 🔸Power generation plants
- 🔸Kilns and boilers
- 🔸High temperature structural applications
Because of its high chromium content, TP309 provides excellent resistance to oxidation up to approximately 1000°C in intermittent service.
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