316L and SS316 (or just 316) steel plates are both marine-grade austenitic stainless steels with excellent corrosion resistance due to added Molybdenum, but the key difference is carbon content: 316L has lower carbon (max 0.03%) for better weldability and less intergranular corrosion risk, while standard 316 has slightly higher carbon (max 0.08%), making 316L generally preferred for welded applications, though both offer similar high performance in chloride environments.
Chemical Composition of SS316 and 316L Steel Plate
| Chemical Composition of SS316 and 316L | ||
|---|---|---|
| Element | SS316 | 316L |
| Carbon | 0.08 | 0.030 max |
| Chromium | 16.0-18.0 | 16.0-18.0 |
| Nickel | 10.0-14.0 | 10.0-14.0 |
| Molybdenum | 2.00-3.00 | 2.00-3.00 |
| Manganese | 2.00 | 2.00 |
| Silicon | 0.75 | 0.75 |
| Nitrogen | 0.10 | 0.10 |
| Phosphorus | 0.045 | 0.045 |
| Sulfur | 0.030 | 0.030 |
Mechanical Properties of sS316 And 316L Steel Plate
| Mechanical Property of SS316 and 316L | 316 | 316L |
|---|---|---|
| Yield Strength, min. (ksi) | 30 | 25 |
| Tensile Strength, min. (ksi) | 75 | 70 |
| Elongation, min. (%) | 40 | 40 |
| Hardness, max. (Rb) | 95 | 95 |
Stainless Steel Standards of sS316 And 316L Steel Plate
| Steel Standards of SS316 and 316L | |
|---|---|
| 316 | 316L |
| ASTM A240 | ASTM A240 |
| ASTM A666 | ASTM A666 |
| ASME SA240 | ASME SA240 |
| AMS 5524 | AMS 5507 |
Key Differences Summarized
Carbon Content: This is the defining factor. 316L (Low Carbon) has max 0.03% C, while 316 has max 0.08% C.
Weldability: 316L's low carbon significantly reduces carbide precipitation during welding, preventing sensitization (intergranular corrosion).
Corrosion Resistance: Both are excellent, but 316L offers superior resistance in welded sections due to its low carbon.
Similarities & Properties
Composition: Both contain Chromium (16-18%), Nickel (10-14%), and Molybdenum (2-3%).
Molybdenum: Adds resistance to pitting and crevice corrosion, especially in chloride-rich (salty) conditions, making them "marine grade".
Applications: Used for marine hardware, chemical processing, food processing, and architectural features.
