What is TP316LN Stainless Steel Seamless Pipe?
TP316LN Seamless Stainless Steel Pipe is supplied for nitrogen-strengthened 316L chemistry for higher yield strength. 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. The governing specification must be stated on the purchase order: ASTM A312 / ASME SA312. 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 + precision cold drawing), it ensures:
- No longitudinal weld seam
- Uniform microstructure
- Superior pressure resistance
- Excellent corrosion performance
The “LN” designation indicates:
- L (Low Carbon ≤0.03%) → Helps limit intergranular corrosion and sensitization
- N (Nitrogen 0.10–0.16%) → Enhances strength and corrosion resistance
Compared with standard 316L, TP316LN offers significantly higher mechanical strength and improved corrosion resistance, making it ideal for critical engineering applications.
Key Features & Technical Advantages
Higher Strength & Reduced Weight
Nitrogen addition increases:
- Yield strength
- Tensile strength
- Design stress capability
Enables thinner wall pipes, reducing material and system costs.
Superior Corrosion Resistance (High PREN)
The combination of Molybdenum + Nitrogen improves:
- Pitting resistance
- Crevice corrosion resistance
- Performance in chloride-rich environments
Excellent Resistance to Intergranular Corrosion
Ultra-low carbon content ensures:
- No chromium carbide precipitation
- Stability in welding heat-affected zones
- Compliance with sensitization-resistant design
Outstanding Cryogenic Performance
TP316LN maintains:
- High toughness at -196°C (LNG temperature)
- Stable mechanical properties at low temperatures
Widely used in LNG, aerospace, and cryogenic storage systems
High Pressure Integrity
Manufactured in accordance with:
- ASTM A312
- EN 10216-5
Ensures safe operation in high-pressure fluid transport 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 316LN stainless steel.
Equivalent Grade
| UNS | Common grade name | EN material number | EN steel name | JIS grade | GB/T grade |
|---|---|---|---|---|---|
| S31653 | 316LN | 1.4429 | X2CrNiMoN17-13-3 | SUS316LN | 022Cr17Ni12Mo2N |
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 composition of Stainless Steel 316LN is carefully balanced to achieve its superior strength and corrosion resistance.
| Cr | Ni | Mo | N | P | S | Mn | Si | C |
|---|---|---|---|---|---|---|---|---|
| 16.00 – 18.00 | 10.00−14.00 | 2.00−3.00 | 0.10 – 0.16 | ≤0.045 | ≤0.03 | ≤2.00 | ≤1.00 | ≤0.035 |
Data source: ASTM A312-25 / ASME SA312 Table 1, TP316LN row ≤ heat-analysis acceptance limits. Confirm the values against the ordered edition and the MTC.
Typical Mechanical Properties
Stainless Steel 316LN is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 515 MPa | ≥ 205 MPa | ≥ 35% | ≤ 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 |
|---|---|---|---|---|---|
| 8.0 g/cm3 | 1370 -1400 °C | 16.0 μm/m·°C (20-100°C) | 16.3 W/m·K (20°C) | 193 GPa | 0.74 × 10⁻⁶ 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.
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.
Industrial Applications
TP316LN seamless pipes are widely used in high-reliability industries:
Nuclear & Power Generation
- Heat exchangers
- Reactor systems
- Control mechanisms
Chemical & Petrochemical
- Urea production
- Acetic acid systems
- High-pressure reactors
Cryogenic & LNG
- LNG pipelines
- Liquid oxygen systems
- Cryogenic storage tanks
Offshore & Marine
- Subsea pipelines
- Hydraulic systems
- Instrumentation tubing
Pharmaceutical & Food Industry
- High-purity process systems
- CIP/SIP cleaning environments
Dimensional Standards & Tolerances
We manufacture TP316LN pipes in strict compliance with international standards:
ASTM / EN / JIS / GB
- ASTM A312
- EN 10216-5
- JIS G3459
- GB/T 14976
Typical tolerances:
- OD tolerance: ±0.2 mm to ±0.5%
- Wall thickness: ±7.5% to ±20%
- Length: per standard or customized
Suitable for precision engineering and critical systems
Quality Assurance & Testing
Inspection scope is agreed on the purchase order. The following are available and applied as specified:
Certification
- EN 10204 3.1 Material Test Certificates (MTC) as standard; 3.2 by arrangement
Testing & Inspection
- PMI (Positive Material Identification), when specified on the purchase order
- Ultrasonic Testing (UT)
- Eddy Current Testing (ET)
- Hydrostatic Testing
Advanced Testing
- ASTM A262 Intergranular Corrosion (IGC)
- Grain size (ASTM E112)
- Flattening & flaring tests
Third-Party Inspection
Available on request — ABS, DNV, BV (Bureau Veritas), TÜV, SGS
Frequently Asked Questions
What sizes are available for TP316LN 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 TP316LN seamless pipe?
ASTM A312 / ASME SA312 is the governing specification for TP316LN seamless pipe. 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 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 TP316LN 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.
