SUS316L Stainless Steel: Composition, Properties and Industrial Applications
Jun 26, 2025
Leave a message
What Is SUS316L Stainless Steel?
SUS316L is the Japanese Industrial Standard (JIS) designation for a low-carbon, molybdenum-bearing austenitic stainless steel. It is the JIS counterpart of ASTM A240 316L (UNS S31603) and EN 1.4404 (X2CrNiMo17-12-2); the cast equivalent of the same alloy family is EN 1.4408, which is used for pump and valve castings. The letter L marks a carbon limit of 0.03% maximum, which suppresses chromium carbide precipitation and keeps the alloy resistant to intergranular corrosion after welding without any post-weld anneal.
Adding 2.00-3.00% molybdenum to a 16-18% chromium and 10-14% nickel base lifts resistance to chloride pitting and crevice attack well above the 304L level. That combination is why SUS316L is the default selection for chemical, marine, pharmaceutical and food-contact equipment.
Chemical Composition of SUS316L
| Element | Content (%) |
|---|---|
| C | 0.030 max |
| Cr | 16.0 - 18.0 |
| Ni | 10.0 - 14.0 |
| Mo | 2.00 - 3.00 |
| Mn | 2.00 max |
| Si | 1.00 max |
| P | 0.045 max |
| S | 0.030 max |
| Fe | Balance |
These limits are aligned across JIS G4303, ASTM A240 and EN 10088-2, so plate, sheet, bar and tube certified to one specification can usually be dual-certified to the others.
Mechanical and Physical Properties
| Property | Typical value |
|---|---|
| Tensile strength, annealed | 485 MPa min |
| 0.2% yield strength | 170 MPa min |
| Elongation in 50 mm | 40% min |
| Hardness | 217 HBW max |
| Density | 7.98 g/cm3 |
| Melting range | 1375 - 1400 C |
| Modulus of elasticity | 193 GPa |
| Thermal conductivity at 100 C | 16.3 W/m.K |
Corrosion, Thermal and Fabrication Behaviour
Chloride resistance: clearly better than 304 or 304L, so the grade suits seawater splash zones, salt spray, bleach and dilute hydrochloric acid.
Acid and alkali service: performs well in moderate concentrations of sulphuric and phosphoric acid and in organic acids such as formic and acetic acid, which is why chemical and pharmaceutical plants rely on it.
Intergranular corrosion: the 0.03% carbon cap prevents sensitisation in the weld heat-affected zone, so no solution anneal is required after welding.
High temperature: suitable for short-term exposure to about 800 C and continuous service near 650 C, above the roughly 600 C long-term ceiling of 304.
Forming and welding: a low work-hardening rate suits bending, roll forming and deep drawing; ER316L filler metal preserves molybdenum in the weld pool and maintains joint corrosion resistance.
Surface finish: 2B, BA, No. 4 brushed and 8K mirror finishes are all produced for sanitary and medical duty.
Where SUS316L Is Used
Chemical and petrochemical plants: reactors, storage tanks, process piping, valves and pumps handling halide-bearing media.
Fertiliser and pharmaceutical lines: chlorine-containing solution tanks, acid reactors and clean-in-place circuits.
Marine and offshore work: desalination modules, ship hardware such as bolts and deck fittings, and coastal architectural cladding.
Food and beverage: fermentation vessels, dairy piping and hygienic tubing in duties where 304 would pit.
Energy and heat transfer: heat exchanger tubes, condensers and flue gas ducting exposed to chlorides.
SUS316L versus SUS304L at a Glance
| Feature | SUS316L | SUS304L |
|---|---|---|
| Molybdenum | 2.00 - 3.00% | None |
| Chloride resistance | High | Moderate |
| Carbon limit | 0.030% | 0.030% |
| Relative cost | Higher | Lower |
| Typical duty | Chemical, marine, medical | Kitchen, light industry |
Frequently Asked Questions
Q: Is SUS316L the same as 316L?
Yes. SUS316L is the JIS name for the same alloy that ASTM lists as 316L or UNS S31603 and EN lists as 1.4404.
Q: What does the L in SUS316L mean?
It means low carbon. The grade is capped at 0.03% carbon so that welded joints resist intergranular corrosion without post-weld heat treatment.
Q: What is the density of SUS316L?
It is 7.98 g/cm3, so a 1 m by 2 m by 5 mm plate weighs about 79.8 kg.
Q: How hot can SUS316L be used?
Continuous service is normally limited to about 650 C with short excursions to roughly 800 C. Above that the 310S family is preferred.
Q: Does SUS316L need annealing after welding?
No. The low carbon content is designed to avoid sensitisation, so annealing is unnecessary for most welded fabrications.
Q: How is SUS316L distinguished from 304?
A molybdenum spot test or a portable XRF analyser is the reliable method, because the two grades look identical after finishing.
Send Inquiry