AISI 316 vs 316L Stainless Steel (UNS S31603)
Both AISI 316 and 316L stainless steel are types of austenitic stainless steel containing molybdenum (Mo). The main difference between 316 and 316L stainless steel is the level of carbon content, weldability, corrosion resistance and mechanical properties. SS316 has a maximum carbon content of 0.08%, while SS316L (UNS S31603) has a maximum carbon content of 0.03%.
Because SS 316L has a much lower carbon content than SS316, welding of 316L stainless steel is better than SS 316. Additionally, AISI 316 may lead to stress corrosion cracking or dimensional instability in service after welding. , therefore, post-weld heat treatment is necessary for stress relief to reduce intergranular corrosion or stress-assisted intergranular corrosion, while SS316L generally does not have these problems.
SS316L can be used in applications where annealing cannot be performed after welding and maximum corrosion resistance is required.
AISI 316 (UNS S31600) and 316L (UNS S31603) are US steel grades, SUS 316 and SUS 316L are Japanese stainless steel grades.
Due to the additional molybdenum in this steel, the overall performance of the steel is better than that of AISI 310 and AISI 304 stainless steel. SS316 also has good resistance to chloride attack and is therefore commonly used in the marine environment.
Material 316L meaning: “3” refers to 300 series chromium-nickel austenitic alloys, L means “Low carbon”.
Difference Between SS316 and SS316L Chemical Composition
The difference between the composition of 316 and 316L stainless steel is summarized in the tables below.
| Chemical Composition SS316 and SS316L (%) | |||||||||
| UN | AISI | C, ≤ | Yes, ≤ | Mn, ≤ | P, ≤ | S, ≤ | No | Cr | Mo |
| UNS S31600 | 316 | 0.08 | 1.00 | 2:00 | 0.045 | 0.030 | 10.0-14.0 | 16.0-18.0 | 2.0-3.0 |
| UNS S31603 | 316L | 0.03 | 1.00 | 2:00 | 0.045 | 0.030 | 10.0-14.0 | 16.0-18.0 | 2.0-3.0 |
Properties of AISI 316L stainless steel
The properties of ASTM AISI 316L stainless steel are listed in the tables below, including mechanical properties and physical properties.
Mechanical Properties SS316 vs SS316L
The tables below provide mechanical properties of AISI 316 vs 316L stainless steel such as yield strength, tensile strength, elongation and hardness in different product shapes and conditions.
| Mechanical Properties SS316 vs SS316L | |||||||||
| ASTM type | AISI type | Conditions | Tensile strength, MPa(ksi), ≥ | 0.2% yield strength, MPa(ksi),≥ | Elongation by 50 mm (2 in.), %, ≥ | Area Reduction, %, ≥ | Brinell hardness (HBW), ≤ | Rockwell hardness (HRBW), ≤ | Product Forms |
| ASTM A276/A276M | 316 | Annealed, hot finished | 515 (75) | 205 (30) | 40 | 50 | – | – | Bars and Shapes |
| 316L | 485 (70) | 170 (25) | 40 | 50 | – | – | |||
| 316 | Annealed, cold finished, Diameter≤12.7 mm (0.5 in.) | 620 (90) | 310 (45) | 30 | 40 | – | – | ||
| 316L | |||||||||
| 316 | Annealed, cold finished, Diameter>12.7 mm (0.5 in.) | 515 (75) | 205 (30) | 30 | 40 | – | – | ||
| 316L | 485 (70) | 170 (25) | 30 | 40 | – | – | |||
| ASTM A580/A580M | 316 | Annealed | 520 (75) | 210 (30) | 35 | 50 | Wire | ||
| 316L | 485 (70) | 170 (25) | 35 | 50 | – | – | |||
| 316 | Cold finished | 620 (90) | 310 (45) | 30 | 40 | – | – | ||
| 316L | |||||||||
| ASTM A240/A240M | 316 | 515 (75) | 205 (30) | 40 | – | 217 | 95 | Plate, Sheet and Strip | |
| 316L | 485 (70) | 170 (25) | 40 | – | 217 | 95 | |||
| ASTM A473/A473M | 316 | Annealed | 515 (75) | 205 (30) | 40 | 50 | – | – | Forged |
| 316L | 450 (65) | 170 (25) | 40 | 50 | – | – | |||
1 MPa = 1 N/mm2
ASTM SAE AISI 316L Physical Properties
The data sheet below provides density, melting point and magnetic permeability of SS 316L.
| Physical properties of AISI 316L | Metric | Imperial |
| Density | 8.0g/cm3 | 0.289 lb/in3 |
| Fusion point | 1375-1400°C | 2500-2550°F |
| Specific thermal capacity | 500 J/kg·K at 20 °C | 0.12 Btu/lb°F at 68°F |
| Electrical resistivity | 0.74 μΩ at 20°C | 29.13 μΩ·in. at 68°F |
| Magnetic permeability | 1.01 (approximate) | – |
| Elastic modulus (Modulus of elasticity) | 193 GPa | 28× 103 ksi |
| Thermal conductivity | 14.0-15.9 W/m·K | 8.09-9.19 Btu/ft·h·°F |
316L heat treatment
Annealing: Recommended annealing temperatures for 316L forged steel are 1400°C (1900°F).
Stress Relief: Stress relief is generally not necessary unless you know or suspect that the environment will cause stress corrosion cracking.
Development notes
Based on 316, many types of steel have been developed. For example, after adding a small amount of titanium (Ti), SS 316Ti was developed. 316N was developed after adding a small amount of nitrogen (N), SS 317L was developed by adding nickel (Ni) and molybdenum (Mo).
Equivalence
AISI 316L SS equivalent to European EN standards (German DIN, British BSI, French NF…), Japanese JIS standards, Chinese GB standards, ISO and more.
| Grade equivalent to AISI 316L | |||||||||||||||||
| USA | European Union | ISO | Japan | China | Australia | India | Russia | Korea | |||||||||
| Standards | Type | Standards | Class (Steel Number) | Standard | Note (ISO number) | Standard | Note | Standards | Note | Standard | Note | Standard | Note | Standard | Note | Standard | Note |
| AISI-SAE; ASTM |
316L (UNS S31603) |
EN 10088-1; EN 10088-2; EN 10088-3 | X2CrNiMo17-12-2 (1.4404) | ISO 15510 | X5CrNiMo17-12-2 (4404-316-03-I) | JIS G4303 | SUS316L | GB/T 20878; GB/T 1220; GB/T 3280 |
00Cr17Ni14Mo2; 022Cr17Ni12Mo2 (New name) |
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Tags: SS316 vs SS316L, 316 vs 316L stainless steel, difference between 316 and 316L
