| Feature | 316 | 316L | 316LN |
|---|---|---|---|
| Type | Austenitic stainless steel | Low-carbon austenitic stainless steel | Low-carbon + nitrogen-enhanced austenitic stainless steel |
| Carbon Content | ≤ 0.08% | ≤ 0.03% | ≤ 0.03% |
| Nitrogen Content | ≤ 0.10% | ≤ 0.10% | 0.06–0.16% |
| Chromium (Cr) | 16–18% | 16–18% | 16–18% |
| Nickel (Ni) | 10–14% | 10–14% | 10–14% |
| Molybdenum (Mo) | 2–3% | 2–3% | 2–3% |
| Yield Strength | ~205 MPa | ~170 MPa | ~250 MPa |
| Tensile Strength | ~515 MPa | ~485 MPa | ~580 MPa |
| Corrosion Resistance | Good | Better for welded structures (less risk of intergranular corrosion) | Best for welded structures and high-pressure environments |
| Applications | Chemical, petrochemical, food processing, marine | Welded tanks, pipes, and pressure vessels | High-pressure, high-temperature, and aggressive chemical environments like oil & gas, nuclear |
| Weldability | Good | Excellent | Excellent; better strength retention after welding due to nitrogen addition |
| Notes | Standard 316; general purpose | "L" = Low carbon, resists sensitization | "LN" = Low carbon + nitrogen, higher strength and corrosion resistance |
Key Points:
316L vs 316: Lower carbon in 316L reduces sensitization (grain boundary carbide precipitation) during welding, preventing intergranular corrosion.
316LN vs 316L: Nitrogen addition increases yield and tensile strength and further enhances corrosion resistance, making it ideal for high-pressure applications.
Choosing the Grade:
Use 316 for standard applications without heavy welding.
Use 316L when welding is frequent or large structures are involved.
Use 316LN for extreme environments requiring high strength and corrosion resistance.
