What is a Seamless TP316LN Stainless Steel Tube?
Seamless TP316LN stainless steel tube (UNS S31653 / W.Nr. 1.4406 / 1.4429) is a nitrogen-strengthened, ultra-low carbon austenitic stainless steel tube designed for demanding applications requiring high strength, corrosion resistance, and structural reliability.
Manufactured via a seamless process (hot piercing + cold drawing/finishing), TP316LN provides:
- Uniform metallurgical structure
- No weld seam defects
- Excellent pressure resistance
- Superior performance under high stress conditions
The designation “LN” indicates:
- L (Low Carbon ≤ 0.03%) → prevents sensitization and intergranular corrosion
- N (Nitrogen-enhanced) → increases strength and improves corrosion resistance
This results in a material with higher mechanical strength than TP316L, while maintaining excellent ductility and corrosion resistance.
Key Features & Technical Advantages
High Strength & Increased Design Stress
Nitrogen addition (0.10%–0.16%) significantly increases yield and tensile strength, enabling thinner wall design and higher allowable stress compared to TP316L.
Excellent Pitting & Crevice Corrosion Resistance
The combination of Molybdenum (Mo) and Nitrogen (N) enhances the PREN value, providing superior resistance in chloride-rich and marine environments.
Intergranular Corrosion Resistance
Ultra-low carbon content (≤ 0.03%) prevents chromium carbide precipitation, ensuring resistance to sensitization during welding.
Excellent Cryogenic Toughness
Maintains outstanding mechanical properties at low temperatures down to -196°C, making it ideal for LNG and cryogenic applications.
High Pressure & Structural Integrity
Manufactured according to:
- ASTM A213
- EN 10216-5
Ensuring reliability in high-pressure and critical service 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 Stainless Steel 316LN.
The composition of Stainless Steel 316LN is carefully balanced to achieve its superior strength and corrosion resistance.
Stainless Steel 316LN is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
These physical properties highlight the material’s ability to perform reliably under a wide range of conditions.
Size & Manufacturing Standards
We supply TP316LN seamless tubes in compliance with global standards:
- ASTM A213 / ASME SA213
- EN 10216-5
- ASTM A269
With strict control of:
- Outer diameter (OD) tolerance
- Wall thickness tolerance
- Surface finish and dimensional accuracy
Common Industrial Applications
TP316LN seamless tubes are widely used in high-strength, high-corrosion, and low-temperature environments:
Nuclear & Power Industry
- Heat exchanger tubes
- Control rod systems
- Reactor components
Chemical & Petrochemical
- Urea production systems
- High-pressure reactors
- Acid handling systems
Cryogenic & LNG Systems
- LNG pipelines
- Liquid oxygen / nitrogen systems
- Cryogenic storage tanks
Offshore & Marine Engineering
- Subsea hydraulic lines
- Instrumentation piping
- Seawater systems
Pharmaceutical & Food Industry
- High-purity process piping
- CIP/SIP systems
Advanced Manufacturing Process
- Raw Material Selection & Billet Heating
- Seamless Hot Piercing Forming
- Cold Drawing / Cold Rolling for Precision
- Solution Annealing Heat Treatment
- Full Non-Destructive Testing (NDT):
- Ultrasonic Testing (UT)
- Eddy Current Testing (ET)
- Hydrostatic Testing
100% Quality Assurance & Certification
We ensure full compliance with international standards:
- EN 10204 3.1 / 3.2 Material Test Certificates (MTC)
- 100% PMI (Positive Material Identification)
- Mechanical & Chemical Testing
- Corrosion Testing:
- Intergranular Corrosion (IGC) per ASTM A262
- Cryogenic impact testing
- Third-Party Inspection:
ABS, TÜV, BV, DNV, SGS available
