What is TP314 Seamless Stainless Steel Pipe?
TP314 Seamless Stainless Steel Pipe is supplied for high-silicon oxidation resistance for high-temperature service. The size range shown (OD 6–1016 mm; WT 0.5–65 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. TP314 (UNS S31400) is a high-silicon heat-resistant austenitic grade and is not listed in the ASTM A312/A213/A269 pipe-and-tube product specifications; supply is therefore quoted against the specification, edition and acceptance criteria agreed on the purchase order. Chemistry, mechanical properties, heat treatment, dimensional tolerance, NDT and certification are reported against that ordered standard and the material heat; typical values on this page are for reference and are not guaranteed acceptance limits.
Manufactured from solid billets using hot piercing and precision rolling processes, TP314 seamless pipes feature:
- Fully homogeneous microstructure
- No weld seams or heat-affected zones (HAZ)
- Superior pressure resistance and structural reliability
Why Choose TP314 for High-Temperature Applications?
The defining feature of TP314 stainless steel is its elevated silicon (Si) content (1.50% – 3.00%), combined with high chromium and nickel levels. This unique composition:
- Forms a dense and stable oxide layer
- Significantly improves oxidation resistance
- Enhances mechanical stability at extreme temperatures
Compared to conventional grades like 304 or 316, TP314 performs reliably in continuous service up to 1150°C (2100°F).
Key Advantages of TP314 Seamless Pipe
1. Exceptional Oxidation and Scaling Resistance
The high chromium (23–26%) and silicon content creates a protective oxide film, allowing long-term exposure to high-temperature oxidizing atmospheres without degradation.
2. Superior Creep and Rupture Strength
TP314 maintains excellent dimensional stability under sustained thermal stress, making it ideal for:
- Furnace components
- Heat treatment systems
- Continuous high-load environments
3. Seamless Structural Integrity
Seamless construction ensures:
- Higher pressure ratings
- Uniform wall thickness and strength
- No weld defects or localized corrosion risks
4. Excellent Thermal Stability
High nickel content improves:
- Resistance to thermal fatigue
- Stability under cyclic heating and cooling conditions
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for TP314 stainless steel.
Equivalent Grade
| UNS | Common grade name | EN material number | EN steel name | JIS grade | GB/T grade |
|---|---|---|---|---|---|
| S31400 | 314 | 1.4841 | X15CrNiSi25-21 | SUH 310 | 16Cr25Ni20Si2 (formerly 1Cr25Ni20Si2) |
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. See the grade designation index.
Chemical Composition
The unique properties of 314 stainless steel are largely due to its balanced composition, with silicon being a key element for high-temperature performance.
| C | Mn | P | S | Si | Cr | Ni |
|---|---|---|---|---|---|---|
| ≤0.25 | ≤2.00 | ≤0.045 | ≤0.030 | 1.50－3.00 | 23.00－26.00 | 19.00－22.00 |
Data source: Heat-analysis acceptance limits shown above are the values commonly specified for TP314 (S31400) high-silicon austenitic steel. Because TP314 is not listed in ASTM A312/A213/A269, the governing specification and edition are those agreed on the purchase order; always confirm the limits against that ordered edition and the mill test certificate (MTC).
Typical Mechanical Properties
Stainless Steel 314 is specifically designed to maintain its strength and shape in high-stress, high-temperature environments.
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 520 MPa | ≥ 205 MPa | ≥ 40% | ≤ 217 HBW |
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 |
|---|---|---|---|---|---|
| 7.9 g/cm3 | 1390 – 1420 °C approx. | 16.5 μm/m·°C (20-100°C) | 14.2 W/m·K (20°C) | 200 GPa | 0.78 × 10-6 0: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.
Size Tolerance Chart (mm)
| NPS Designator (Inches) | Permissible Variations in Outside Diameter (Inches) |
| 1⁄8 to 1 1⁄2, inclusive | Over: 1⁄64 in. (0.015 in.) |
| Under: 1⁄32 in. (0.031 in.) | |
| Over 1 1⁄2 to 4, inclusive | Over: 1⁄32 in. (0.031 in.) |
| Under: 1⁄32 in. (0.031 in.) | |
| Over 4 to 8, inclusive | Over: 1⁄16 in. (0.062 in.) |
| Under: 1⁄32 in. (0.031 in.) | |
| Over 8 to 18, inclusive | Over: 3⁄32 in. (0.093 in.) |
| Under: 1⁄32 in. (0.031 in.) | |
| Over 18 to 26, inclusive | Over: 1⁄8 in. (0.125 in.) |
| Under: 1⁄32 in. (0.031 in.) | |
| Over 26 to 34, inclusive | Over: 5⁄32 in. (0.156 in.) |
| Under: 1⁄32 in. (0.031 in.) | |
| Over 34 to 48, inclusive | Over: 3⁄16 in. (0.187 in.) |
| Under: 1⁄32 in. (0.031 in.) |
Tolerance basis: permitted variations per the governing specification stated on this page and the applicable general-requirements standard (ASTM A999 / ASME SA999) for the ordered product form; the wall-thickness and length variations in this section follow the same basis.
The wall thickness tolerances are defined by the nominal wall thickness (t) and the outside diameter (D).
1. Minimum Wall Thickness
The minimum wall thickness at any point on the pipe shall not be more than {12.5%} under the nominal (specified) wall thickness.
2. Maximum Wall Thickness (Percentage Over Nominal)
The maximum allowable wall thickness variation depends on the size and the t/D ratio (ratio of nominal wall thickness to ordered outside diameter):
| NPS Designator (Inches) | t/D Ratio | Permissible Variation (Over Nominal WT) |
| 1/8 to 2, inclusive | All ratios | +20.0% |
| 3 to 18, inclusive | t/D ≤ 5% | +22.5% |
| 3 to 18, inclusive | t/D >5% | +15.0% |
| 20 and larger (Seamless) | t/D ≤ 5% | +22.5% |
| 20 and larger (Seamless) | t/D >5% | +15.0% |
| 20 and larger (Welded) | All ratios | +17.5% |
For pipe ordered to a Specific Cut Length, the standard tolerance is +1⁄8 in. [3.2 mm], -0 in. [0 mm].
Pipe is typically supplied in Single Random Lengths (17 to 24 ft) or Double Random Lengths (38 to 40 ft), unless otherwise specified.
Disclaimer: These tolerances are based on ASTM A999/A999M general dimensional requirements commonly referenced by ASTM A312 and ASTM A790. The full and most current specification document must always be consulted for official design and procurement purposes.
Common Industrial Applications
TP314 is widely used in industries requiring extreme heat resistance and structural stability:
Heat Treatment & Metallurgy
- Radiant tubes
- Furnace muffles
- Retorts and conveyors
Petrochemical Processing
- High-temperature gas pipelines
- Heat exchangers under oxidizing atmospheres
Power Generation
- Boiler components
- Superheater and reheater tubes
Glass & Ceramics Industry
- Kiln linings
- Thermal processing equipment
Advanced Manufacturing Process & Quality Control
Our TP314 seamless pipes are produced under strict quality systems to ensure global compliance and reliability:
1. Billet Heating
Uniform heating of high-purity 314 stainless steel ingots for optimal workability.
2. Hot Piercing
Rotary piercing to form a seamless hollow shell with consistent structure.
3. Cold Rolling / Drawing
Precision dimensional control to achieve exact OD and wall thickness tolerances.
4. Solution Annealing
- Temperature:1050°C – 1150°C
- Rapid quenching to restore corrosion resistance and refine grain structure
5. Comprehensive Inspection
Non-Destructive Testing (NDT):
- Eddy Current Testing (ECT)
- Ultrasonic Testing (UT)
Pressure Testing:
- Hydrostatic testing for leak-proof assurance
Why Choose Our TP314 Seamless Pipes?
- Full compliance with international standards
- Stable high-temperature performance up to 1150°C
- Strict quality control and traceability
- Custom sizes and specifications available
We specialize in high-performance stainless steels, Super Duplex, and nickel alloys, delivering reliable solutions for the most demanding industrial environments.
Frequently Asked Questions
What sizes are available for TP314 seamless pipe?
The overall range is OD 6–1016 mm; WT 0.5–65 mm. Requirements outside this range are reviewed against mill capability on request.
Which specification governs TP314 seamless pipe?
TP314 (S31400) is not a listed grade in ASTM A312, A213 or A269, so the governing specification is the standard, edition and acceptance criteria agreed on the purchase order. State the required standard and edition on the RFQ; testing and certification are then reported against that ordered edition and the 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 follow the specification and edition agreed on the purchase order (TP314/S31400 is not listed in ASTM A312/A213/A269); 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 NPS and schedule (or actual OD and wall), 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 tube form, see the TP314 seamless tube. To compare other grades and size combinations, browse the Stainless Steel Seamless Tube category. Minimum order quantity and lead time are confirmed on enquiry against the ordered grade, size and quantity.
