What Is a Seamless Stainless Steel TP310MoLN Tube?
High-Alloy Urea-Grade Stainless Steel for Chloride & Carbamate Environments
TP310MoLN Seamless Stainless Steel Tube is supplied for urea-grade corrosion resistance with molybdenum and nitrogen alloying. 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 A213 / ASME SA213, confirm UNS S31050 against the order. 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 via seamless hot extrusion and precision cold finishing, the product ensures:
- Uniform grain structure
- No longitudinal weld seam
- Excellent resistance to localized corrosion
- Superior pressure and mechanical integrity
The “MoLN” designation represents:
- Mo (Molybdenum) → Enhanced resistance to pitting and crevice corrosion
- L (Low Carbon, ≤0.025% per ASTM A213 Table 1) → Reduces the risk of sensitization and intergranular corrosion
- N (Nitrogen) → Improves strength, stability, and PREN value
TP310MoLN is widely recognized as a premium urea-grade stainless steel tube, especially for ammonium carbamate service environments.
Key Features & Technical Advantages
Exceptional Urea Carbamate Resistance
Designed for urea synthesis plants, TP310MoLN provides outstanding resistance to:
- Ammonium carbamate
- Urea solutions
- High-pressure CO₂/NH₃environments
Superior Corrosion Resistance (High PREN)
High alloy content significantly improves corrosion resistance:
- Chromium: 24.0% – 26.0%
- Molybdenum: 1.6% – 2.6%
- Nitrogen: 0.09% – 0.15%, enhancing stability
Result:High PREN (Pitting Resistance Equivalent Number), far exceeding 316L and 310.
Excellent Resistance to SCC (Stress Corrosion Cracking)
The combined effect of high Nickel (~22%) and Nitrogen provides:
- Strong resistance to chloride-induced SCC
- Reliable performance in marine, offshore, and desalination systems
High Mechanical Strength
Nitrogen strengthening significantly increases:
- Yield strength
- Load-bearing capacity
- Design stress limits
Allows thinner wall design, reducing system weight and cost.
Fully Austenitic & Non-Magnetic
- Stable austenitic microstructure
- Excellent cold working capability
- Non-magnetic in annealed condition
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 TP310MoLN Tube.
The composition is carefully controlled to ensure a ferrite-free and fully austenitic structure suitable for urea-grade service.
Equivalent Grade
| UNS | Common grade name | EN material number | EN steel name | JIS grade | GB/T grade |
|---|---|---|---|---|---|
| S31050 | 310MoLN / 2RE69 | 1.4466 / 1.4465 (qualified correspondence) | Not confirmed | Not confirmed | Not confirmed |
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
| C | Si | Mn | P | S | Cr | Ni | Mo | N |
|---|---|---|---|---|---|---|---|---|
| ≤0.025 | ≤0.40 | ≤2.00 | ≤0.020 | ≤0.030 | 24.00–26.00 | 21.00–23.00 | 2.00–3.00 | 0.10–0.16 |
Data source: ASTM A213/A213M Table 1, TP310MoLN (UNS S31050) row — heat-analysis acceptance limits: C ≤ 0.025, Mn ≤ 2.00, P ≤ 0.020, S ≤ 0.030, Si ≤ 0.40, Cr 24.0–26.0, Ni 21.0–23.0, Mo 2.0–3.0, N 0.10–0.16. Confirm against the ordered edition and the MTC.
Stainless Steel TP310MoLN is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 580 MPa (wall ≤ 6 mm); ≥ 540 MPa (wall > 6 mm) | ≥ 270 MPa (wall ≤ 6 mm); ≥ 255 MPa (wall > 6 mm) | ≥ 25% | ≤ 217 HBW / 95 HRB |
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 | 1390 – 1440 °C approx. | 16.5 μm/m·°C (20-100°C) | 16.0 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.
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
TP310MoLN seamless tubes are widely used in critical and aggressive environments:
Urea & Fertilizer Industry
- Urea strippers
- Carbamate condensers
- High-pressure synthesis loops
Oil & Gas / Offshore
- Chemical injection lines
- Manifolds and risers
- Chloride-rich service systems
Marine & Desalination
- Seawater heat exchangers
- Desalination plant piping
Pulp & Paper
- Bleaching systems
- Digester components
Quality Assurance & Certification
TP310MoLN tubes are supplied with the following documentation, applied as agreed on the purchase order:
- EN 10204 3.1 Material Test Certificates (MTC) as standard; 3.2 by arrangement
Inspection & Testing
- PMI (Positive Material Identification), when specified
- Ultrasonic Testing (UT), when specified
- Eddy Current Testing (ET), when specified
- Hydrostatic Testing, when specified
Advanced Testing
- Huey Test (ASTM A262 Practice C)
- Intergranular Corrosion (IGC) Test
- Grain size analysis
- Mechanical property verification
Third-Party Inspection
- ABS
- DNV
- BV (Bureau Veritas)
- TÜV
- SGS
Frequently Asked Questions
What sizes are available for TP310MoLN seamless tube?
Which specification governs TP310MoLN seamless tube?
What inspection documents are provided?
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 TP310MoLN 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.
