Key Feature

The Ultimate Dual-Protection Piping Alloy. Combines molybdenum-enhanced corrosion resistance with low-carbon weldability for maximum performance in critical applications.

The gold standard for demanding environments requiring both welding integrity and extreme corrosion resistance.

Common Designations

UNS S31603
AISI 316L
ASTM A312 TP316L (Seamless/Welded)
ASTM A358 TP316L (EFW)
EN 1.4404, X2CrNiMo17-12-2
JIS SUS316L

ASTM A312 TP316L is the primary specification for critical service piping.

Chemical Composition (Typical wt.%)

C: ≤ 0.030Cr: 16.0 - 18.0
Ni: 10.0 - 14.0
Mo: 2.0 - 3.0Mn: ≤ 2.00
Si: ≤ 0.75
P: ≤ 0.045
S: ≤ 0.030

Critical combination: ≤0.03% Carbon + 2-3% Molybdenum for dual protection.

Mechanical Properties

Tensile Strength: ≥ 485 MPa
Yield Strength: ≥ 170 MPa
Elongation: ≥ 40%
Hardness: ≤ 217 HB

Slightly lower yield strength than standard 316, but superior corrosion performance.

Physical Properties

Density: 7.98 g/cm³
Melting Range: 1375 - 1400 °C
Thermal Expansion: 16.0 × 10⁻⁶/K (20-100°C)
Non-magnetic when annealed

Slightly denser than 304/304L due to molybdenum content.

Pressure Ratings

Schedule 5S/10S: Thin wall for low pressure
Schedule 40S: Standard process piping
Schedule 80S: High pressure service
Schedule 160: Severe service

Same dimensional standards as 316; pressure ratings use 316L yield strength.

Corrosion Resistance

Superior: Excellent resistance to chlorides, acids, pitting, and crevice corrosion. Maintains full corrosion resistance in welded conditions.

PREN*: 25-27 - Higher than 316 due to better microstructural stability.

Temperature Limits

Continuous Service (corrosion): Up to 425°C
Higher Temp Service: Up to 870°C
Cryogenic Service: Excellent down to -196°C

Lower maximum temperature for corrosion service than 316, but better weld performance.

Welding Advantages

• No Sensitization in HAZ
• No Post-Weld Annealing required
• Maintains Corrosion Resistance• Suitable for Thick Sections• All Standard Methods applicable

Eliminates costly post-weld treatments and ensures long-term reliability.

Surface Finishes

• Mill Finish: For general industrial
• Polished: For sanitary applications (Ra ≤ 0.8 μm)
• Electropolished: For ultra-high purity
• Bead Blasted: For aesthetic applications

Various finishes available for specific industry requirements.

Key Standards

ASTM A312 TP316L: Pressure Pipe
ASTM A358 TP316L: EFW Pipe
ASTM A269 TP316L: Tubing
ASTM A270: Sanitary Tubing
EN 10216-5: Pressure Tubes
ASME SA312: Code Construction
3-A Sanitary Standards

Meets both pressure piping and sanitary industry standards.

Common Applications

• Pharmaceutical/Biotech: WFI systems, clean steam, process piping, bioreactors
• Chemical Processing: Acid transport, corrosive chemical lines, reactor systems
• Marine/Offshore: Seawater systems, desalination plants, ballast piping
• Food & Beverage: Salt brine lines, acidic product transfer, CIP systems
• Semiconductor: Ultra-pure water, chemical distribution, process gases
• Medical: Implant manufacturing, sterile processing, laboratory systems
• Nuclear: Moderator systems, auxiliary piping, waste processing

Specifically selected where both corrosion resistance and weld integrity are critical.