What Is a Seamless Stainless Steel TP347 Tube?
Niobium-Stabilized Austenitic Stainless Steel for High-Temperature & Corrosion-Resistant Service
1. What is a Seamless TP347 Stainless Steel Tube?
TP347 Seamless Stainless Steel Tube is supplied for niobium stabilization for resistance to sensitization during high-temperature exposure. The size range shown (OD 6–257 mm; WT 0.5–35 mm) is the overall capability across this product family, not a per-grade commitment. Confirm the specific OD × WT × length combination for the ordered grade in the quotation. The governing specification must be stated on the purchase order: ASTM A269 or ASTM A213 / ASME SA213, subject to service. Chemistry, mechanical properties, heat treatment, dimensional tolerance, NDT and certification must be reported against the ordered standard and material heat; do not treat typical values as guaranteed acceptance limits.
Manufactured through a seamless process (hot piercing + cold drawing/finishing) from a solid billet, TP347 tubes provide:
- Uniform metallurgical structure
- Excellent pressure resistance
- No longitudinal weld seam
The key feature of TP347 is the addition of Niobium (Nb), which stabilizes carbon and limits chromium carbide precipitation at grain boundaries. This improves resistance to sensitization and intergranular corrosion (IGC) during prolonged exposure to elevated temperatures or welding, subject to the welding procedure and service temperature.
2. Key Features & Technical Advantages
Excellent Intergranular Corrosion Resistance
Niobium stabilization limits carbide precipitation, greatly reducing sensitization in the heat-affected zone (HAZ).
High-Temperature Performance (Up to 815°C)
Performs reliably in continuous service up to 815°C (1500°F) with strong oxidation and scaling resistance.
Improved Creep Strength
Compared with standard 304/304L, TP347 offers better creep resistance and structural stability under long-term high-temperature stress.
Excellent Weldability
Can be welded using standard methods without requiring post-weld heat treatment to restore corrosion resistance.
High Pressure Integrity
Seamless manufacturing ensures compliance with ASTM A213 / ASME SA213 / EN 10216-5, suitable for critical pressure systems.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Seamless Stainless Steel TP347 Tube.
Equivalent Grade
| UNS | Common grade name | EN material number | EN steel name | JIS grade | GB/T grade |
|---|---|---|---|---|---|
| S34700 | 347 | 1.4550 | X6CrNiNb18-10 | SUS347 | 06Cr18Ni11Nb / 0Cr18Ni11Nb |
Grade correspondence does not make ASTM, ASME, EN, JIS and GB delivery requirements interchangeable. Confirm chemistry, heat treatment, mechanical properties, dimensions, testing and certification against the purchase specification. Approximate or unconfirmed correspondences retain their qualification. See the grade designation index.
Chemical Composition
The composition of Stainless Steel 347 is carefully balanced to achieve its superior high-temperature stability and corrosion resistance.
| Grade | C | Cr | Ni | Mn | P | S | Si | Other |
|---|---|---|---|---|---|---|---|---|
| 347 | ≤0.08 | 17.00–20.00 | 9.00–13.00 | ≤2.00 | ≤0.045 | ≤0.030 | ≤1.00 | Nb 10×C–1.10 |
| 347H | 0.04–0.10 | 17.00–19.00 | 9.00–13.00 | ≤2.00 | ≤0.045 | ≤0.030 | ≤1.00 | Nb 8×C–1.10 |
Data source: ASTM A213-25 / ASME SA213 Table 1, TP347 row ≤ heat-analysis acceptance limits. Confirm the values against the ordered edition and the MTC.
Stainless Steel 347 is specifically designed to maintain its strength and shape in high-temperature, high-stress environments.
Typical Mechanical Properties
| Grade | Yield strength ksi(MPa) | Tensile Strength ksi(MPa) | Elongation % | Hardness Brinell/Vickers | Hardness Rockwell |
|---|---|---|---|---|---|
| 347 | ≥30(205) | ≥75(515) | ≥35 | ≤192 HBW/200HV | ≤90HRB |
| 347H | ≥30(205) | ≥75(515) | ≥35 | ≤192 HBW/200HV | ≤90HRB |
Note: Typical values for reference only — not acceptance limits. Mechanical properties are reported on the MTC against the ordered standard, product form, condition and test temperature.
Typical Physical Properties
These physical properties highlight the material’s ability to perform reliably under a wide range of conditions.
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
|---|---|---|---|---|---|
| 8.0 g/cm³ | 1398 – 1454 °C | 16.6 μm/m·°C (20-100°C) | 16.3 W/m·K (20°C) | 193 GPa | 0.72 x 10⁻⁵ Ω·m (20°C) |
Note: Typical values for reference only — not acceptance limits. Physical and mechanical properties are reported on the MTC against the ordered standard, product form and condition.
ASTM A1016/A1016M Tube Size Tolerance Chart
Size Tolerance Chart (mm)
| Specified Outside Diameter (OD) (Inches) | Permissible Variations in OD (± Inches) |
|---|---|
| 1⁄2 to 1 | ±0.005 |
| Over 1 to 1-1⁄2 | ±0.008 |
| Over 1-1⁄2 to 2 | ±0.010 |
| Over 2 to 2-1⁄2 | ±0.012 |
| Over 2-1⁄2 to 3-1⁄2 | ±0.014 |
| Over 3-1⁄2 to 5 | ±0.020 |
Tolerance basis: permitted variations per the governing specification stated on this page and the applicable general-requirements standard (ASTM A1016 / ASME SA1016) for the ordered product form; the wall-thickness and length variations in this section follow the same basis.
| Specified Outside Diameter (OD) (Inches) | Specified Wall Thickness (WT) (Inches) | Permissible Variation (± Inches) |
|---|---|---|
| 1⁄2 to 1 (Inclusive) | 0.025 to 0.065(Inclusive) | ±0.010 |
| Over 0.065to 0.134 (Inclusive) | ±0.012 | |
| Over 1 to 1-1⁄2 (Inclusive) | 0.025 to 0.065 (Inclusive) | ±0.010 |
| Over 0.065 to 0.134 (Inclusive) | ±0.012 | |
| Over 1-1⁄2 to 2 (Inclusive) | 0.025 to 0.049 (Inclusive) | ±0.011 |
| Over 0.049 to 0.083 (Inclusive) | ±0.012 | |
| Over 0.083 to 0.148 (Inclusive) | ±0.014 | |
| Over 2 to 2-1⁄2 (Inclusive) | 0.032 to 0.065 (Inclusive) | ±0.013 |
| Over 0.065 to 0.109 (Inclusive) | ±0.015 | |
| Over 0.109 to 0.165 (Inclusive) | ±0.017 | |
| Over 2-1⁄2 to 3-1⁄2 (Inclusive) | 0.032 to 0.165 (Inclusive) | ±0.020 |
| Over 0.165 to 0.220 (Inclusive) | ±0.025 | |
| Over 3-1⁄2 to 5 (Inclusive) | 0.083 to 0.165 (Inclusive) | ±0.025 |
| Over 0.165 to 0.220 (Inclusive) | ±0.030 |
Length Tolerance
For Specific Cut Lengths, the standard tolerance is +1⁄8 in. [3 mm], -0 in. [0 mm].
Important Note: The values presented here are based on the dimensional tolerance tables in ASTM A1016/A1016M (General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes), contains other essential requirements like straightness and details for tubes with ODs outside of this range. Always consult the latest official standard for design and procurement.
Common Industrial Applications
Seamless TP347 stainless steel tubes are widely used in high-temperature and cyclic thermal environments, including:
Power Generation
- Superheater tubes
- Reheater tubes
- Boiler headers
Aerospace & Energy Systems
- Exhaust manifolds
- Jet engine components
- High-temperature ducts
Petrochemical & Refinery
- Heat exchanger tubes
- Catalytic cracking units
- Process piping systems
Waste & Incineration
- Furnace components
- Combustion chambers
- High-temperature flue gas systems
Advanced Manufacturing Process
- Raw Material Selection & Billet Heating
Controlled heating to achieve optimal grain structure. - Rotary Piercing
Formation of hollow shell without internal defects. - Cold Drawing / Cold Rolling
Achieves precise dimensions and superior surface finish. - Solution Annealing
Heat treatment to restore corrosion resistance and mechanical properties. - Full Non-Destructive Testing (NDT)
- Ultrasonic Testing (UT)
- Eddy Current Testing (ET)
- Hydrostatic Testing
100% Quality Assurance & Certification
We ensure full compliance with international quality standards:
- Material Certificates: EN 10204 3.1 as standard; 3.2 on arrangement
- Traceability: Full heat number traceability
- Chemical & Mechanical Testing: PMI, hardness, tensile, flattening, flaring
- Corrosion Testing: Intergranular Corrosion (IGC) per ASTM A262
- Third-Party Inspection: ABS, TÜV, BV, DNV, SGS
Frequently Asked Questions
What sizes are available for TP347 seamless tube?
The overall range is OD 6–257 mm; WT 0.5–35 mm. Requirements outside this range are reviewed against mill capability on request.
Which specification governs TP347 seamless tube?
ASTM A269 or ASTM A213 / ASME SA213, subject to service is the governing specification for TP347 seamless tube. The edition in force at order time is stated on the quotation and purchase order; chemistry, mechanical properties, heat treatment, dimensions and testing are reported against the ordered standard and material heat.
What inspection documents are provided?
Each order is documented with a mill test certificate stating heat chemistry and mechanical test results. EN 10204 3.1 certification, hydrostatic testing, eddy-current or ultrasonic inspection and PMI are performed when specified in the purchase order.
Technical review: page data reviewed by the Xinzhe technical desk on 2026-09-27. Chemistry acceptance limits are compiled from the governing ASTM/ASME specification stated on this page; mechanical and physical values are typical reference data and are not acceptance guarantees. Values must be confirmed against the standard edition in force at order time and the material test certificate.
Ready to Request a Quotation?
Send the size (OD and wall or schedule), quantity, length, end finish and the inspection items you need as acceptance criteria — you will get a written quotation stating the specification and edition, delivery condition, documents included and lead time.
For the same grade in pipe form, see the TP347 seamless pipe. To compare other grades and size combinations, browse the Stainless Steel Seamless Pipe category. Minimum order quantity and lead time are confirmed on enquiry against the ordered grade, size and quantity.
