ASTM A312 TP347 Stainless Steel Seamless Pipe
Jan 26, 2026
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What is ASTM A312 TP347?
ASTM A312 TP347 is a niobium-tantalum stabilized austenitic stainless steel seamless pipe, with better high-temp stability than Ti-stabilized grades, used in nuclear, power and high-temp process piping.
Equivalent Grades (Horizontal)UNS: S34700 | JIS: SUS347 | GB: 06Cr18Ni11Nb | EN: X6CrNiNb18-10 | W.Nr.: 1.4550
Chemical Composition (wt%, Horizontal)C: ≤0.08 | Si: ≤1.00 | Mn: ≤2.00 | P: ≤0.045 | S: ≤0.030 | Cr: 17.00-19.00 | Ni: 9.00-13.00 | Nb+Ta: ≥10×C | Fe: Balance
| UNS No | Grade | C | Si | Mn | P | S | Cr | Mo | Ni | N | Other |
| S34700 | 347 | 0.08 | 0.75 | 2.00 | 0.045 | 0.030 | 17.00/19.00 | – | 9.00/13.00 | – | Cb:10xC1.00 |
Key Properties (20°C, Annealed, Horizontal)Density: 7.93g/cm³ | Melting Point: 1400-1450°C | Tensile Strength: ≥515N/mm² | Yield Strength: ≥205N/mm² | Elongation: ≥40% | Hardness: ≤201HB
Core Characteristics
Excellent post-weld intergranular corrosion resistance
Superior high-temperature stability (up to 900°C)
Good weldability and creep resistance
Ideal for nuclear, high-temp process and furnace piping
TP321 vs TP347 (Horizontal)Stabilizer: 321 (Ti) | 347 (Nb+Ta) | High-Temp Stability: 321 (Good) | 347 (Superior) | Applications: 321 (General) | 347 (Nuclear/High-Temp)
Stainless Steel Suppliers
If you have project requirements for stainless steel, we welcome your order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com
Testing and Documentation: Factory test certificate, EN 10204 3.1, chemical report, mechanical report, destructive testing report, non-destructive testing report, PMI test report, visual inspection report, third-party inspection report, NABL certified laboratory report.
Packaging: Wooden crate packaging, bubble wrap packaging, steel strapping, or packaging according to customer requirements.
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