What is the composition of SS 347 material pipe?
Jul 07, 2025
Leave a message
Why Know the Composition of SS 347 pipe?
SS 347 stainless steel round pipe is a niobium-stabilized austenitic stainless steel designed to resist intergranular corrosion in high-temperature and welded applications. Understanding its exact composition is crucial for engineers, material buyers, and fabricators who need thermal stability, corrosion resistance, and weldability without post-weld heat treatment.
What is the equivalent of 347 stainless steel?
| Standard System | Grade/Designation | UNS Number |
|---|---|---|
| ASTM (US) | 347 | S34700 |
| EN (Europe) | 1.4550 X10CrNiNb18-9 |
|
| JIS (Japan) | SUS347 | |
| GB (China) | 06Cr18Ni11Nb | S34778 |
| DIN (Germany) | X10CrNiNb189 |
SS 347 Material Specification
SS 347 is a niobium-stabilized austenitic stainless steel designed for high-temperature strength and resistance to intergranular corrosion. It is standardized across multiple global specifications:
| Standard | Specification / Grade |
|---|---|
| UNS | S34700 |
| ASTM A240 | SS 347 plate, sheet, strip |
| ASTM A312 | SS 347 seamless and welded pipe |
| ASTM A213 | SS 347 seamless tubes for heat exchangers |
| ASTM A182 | SS 347 forged fittings, flanges |
| EN / DIN | 1.4550 / X6CrNiNb18-10 |
| AWS A5.9 | ER347 (welding wire) |
What is the chemical composition of SS 347 pipe?
| Element | Percentage (%) |
|---|---|
| Chromium (Cr) | 17.0 – 19.0 |
| Nickel (Ni) | 9.0 – 13.0 |
| Niobium (Nb / Cb) | ≥ 10 × C (min ~0.3 – 1.0) |
| Carbon (C) | ≤ 0.08 |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.03 |
| Iron (Fe) | Balance |
Key Element: Niobium (Nb) is the defining addition in SS 347. It prevents intergranular corrosion by binding carbon and preventing chromium carbide precipitation at grain boundaries during welding or exposure to 425–850°C.
What Is SS 347 Industrial Pipe Used for in High-Temperature Applications?
SS 347 stainless steel is widely used in high-temperature environments (typically up to 870°C / 1600°F) where resistance to thermal cycling, weld decay, and oxidation is critical. Thanks to its niobium content, it resists sensitization and intergranular corrosion even after prolonged heat exposure.
Common High-Temperature Applications Include: Heat exchangers and superheaters, Boiler tubes and refinery heaters, Jet engine exhaust parts, Reformer tubes in petrochemical plants, Steam piping and high-temperature pressure vessels, Welded structures that cannot be heat-treated post-welding.
Need Certified SS 347 Materials pipe ?
We supply SS 347 pipes, SS 347 seamless tubes for heat exchangers ,SS 347 seamless and welded pipe,SS 347 Mirror Polished steel pipe,SS 347Stainless steel Bright annealed pipe ,SS 347 Stainless Steel Polished Pipe,SS 347 Stainless steel pickling pipe with full traceability, MTCs (EN 10204 3.1), and quick lead times.
👉 Contact our team today for:Chemical composition certificates,Custom machining or cut-to-size service,Export-ready packaging and global delivery!
Send Inquiry