Alloy 316 / 316L (UNS S31600 / S31603)
Stainless steel types 1.4401 and 1.4404 are also known as grades 316 and 316L respectively. Grade 316 is an austenitic grade second only to 304 in commercial importance. 316 stainless steel contains an addition of molybdenum that gives it improved corrosion resistance. This is particularly apparent for pitting and crevice corrosion in chloride environments.
316L, the low carbon version of 316 stainless steel, is immune to grain boundary carbide precipitation (sensitisation). It is common practice for 316L to be dual certified as 316 and 316L. The low carbon chemistry of 316L combined with an addition of nitrogen enables 316L to meet the mechanical properties of 316. Due to its austenitic microstructure, SS316/316L has very good impact strength both at room temperature and at cryogenic temperatures.
Specifications
- UNS: S31600 / S31603
- ASTM: A276 (Bars), A182 F316/F316L (Forgings), A240 (Plates), A312 (Pipes)
- EN / DIN: 1.4401 (316) / 1.4404 (316L)
- Structure: Austenitic
- Condition Supplied: Hot worked & solution annealed
Data Tables
Chemical Composition:
| C | Mn | P | S | Si | Cr | Ni | Ti | Mo | N | Cu | Fe | Co | Nb (+Ta) | V | W | Al | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | 16.5 | 10 | 2 | ||||||||||||||
| Max | 0.04 | 2 | 0.04 | 0.03 | 1 | 18.5 | 13 | 2.5 | 0.11 | Bal |
Mechanical Properties:
| Material Grade | ASTM Standard | Desgnation(EN /UNS) | Yield Strength (MPa) | Yield Strength (KSI) | Tensile Strength (MPa) | Tensile Strength (KSI) | Elongation (%) | Reduction of Area (%) | Hardness(HRC/HBWMax) | Condition | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| SS 316 / 316L | ASTM A276 / A182 / A479 | EN 1.4401/1.4404( S31600/S31603) | 205 | 29.73279 | 515 | 74.69457 | 30 | 50 | 237 HBW-NACE | Solution Annealed |
Physical Properties:
| Material Grade | Density (g/cm³) | Melting Range (°C) | Modulus of Elasticity (GPa) | Thermal Conductivity (W/m·K) | Thermal Expansion (×10⁻⁶ /°C) | Electrical Resistivity (µΩ·m) | Magnetic Behavior |
|---|---|---|---|---|---|---|---|
| 316 / 316L | 7.98 | 1370–1400 | 193 | 14–16 | 16 | 0.72 | Non-magnetic |
Key Features
- Excellent resistance to pitting and crevice corrosion
- Superior performance in chloride and marine environments
- Very good weldability and formability
- High toughness, even at cryogenic temperatures
- 316L resists intergranular corrosion after welding
Applications
- Chemical processing equipment
- Marine and offshore components
- Heat exchangers and pressure vessels
- Pharmaceutical and food processing machinery
- Forged shafts, flanges, and valves