Stainless Steel 316L Grade – SUS316L
Stainless Steel 316L (SUS316L) is the low-carbon version of the molybdenum-bearing austenitic grade 316. With carbon restricted to 0.03% maximum, 316L resists carbide precipitation (sensitisation) in the heat-affected zone during welding, making it the preferred choice for welded pipes, fittings, vessels, and process equipment operating in chloride-rich and corrosive environments. It combines excellent corrosion resistance, good formability, and outstanding weldability, and is widely specified across pharmaceutical, marine, chemical, food and beverage, and medical industries.
Chemical Composition – SS 316L Grade
| Element | Min (%) | Max (%) |
|---|
| Chromium (Cr) | 16.00 | 18.00 |
| Nickel (Ni) | 10.00 | 14.00 |
| Molybdenum (Mo) | 2.00 | 3.00 |
| Carbon (C) | — | 0.030 |
| Manganese (Mn) | — | 2.00 |
| Silicon (Si) | — | 0.75 |
| Phosphorus (P) | — | 0.045 |
| Sulphur (S) | — | 0.030 |
| Nitrogen (N) | — | 0.10 |
| Iron (Fe) | Balance |
Mechanical Properties – SS 316L Grade
| Property | Value |
|---|
| Tensile Strength (min) | 485 MPa (70 ksi) |
| Yield Strength – 0.2% Proof (min) | 170 MPa (25 ksi) |
| Elongation (min) | 40% |
| Hardness (Brinell, max) | 217 HB |
| Hardness (Rockwell B, max) | 95 HRB |
| Density | 8.00 g/cm³ |
Physical Properties – SS 316L Grade
| Property | Value |
|---|
| Density | 8.00 g/cm³ |
| Melting Range | 1370–1400°C (2500–2550°F) |
| Thermal Conductivity (at 100°C) | 16.3 W/m·K |
| Electrical Resistivity | 740 nΩ·m |
| Modulus of Elasticity | 193 GPa |
| Coefficient of Thermal Expansion (0–100°C) | 16.0 × 10⁻⁶/°C |
| Specific Heat Capacity | 500 J/kg·K |
Corrosion Resistance – SS 316L Grade
Grade 316L offers excellent resistance to pitting and crevice corrosion in chloride-containing environments due to its 2–3% molybdenum content, with a Pitting Resistance Equivalent Number (PREN) of approximately 24–26 — significantly higher than Grade 304. Because of its low carbon content, 316L is highly resistant to sensitisation and intergranular corrosion after welding, without requiring post-weld annealing. It resists oxidation up to 870°C in intermittent service. For higher chloride or seawater immersion service, super-austenitic or duplex grades should be considered.
International Grade Equivalents – SS 316L
| Standard | Designation | Description |
|---|
| USA (AISI/ASTM/UNS) | 316L / S31603 | American standard |
| Europe (EN) | 1.4404 / X2CrNiMo17-12-2 | European standard |
| Japan (JIS) | SUS 316L | Japanese Industrial Standard |
| BS (United Kingdom) | 316S11 / 316S13 | British Standard designation |
| GB (China) | 022Cr17Ni12Mo2 | Chinese national standard |
| ISO | X2CrNiMo17-12-2 | International Organization for Standardization |
| France (AFNOR) | Z2CND17-12 | French standard |
| Germany (DIN/Werkstoff) | 1.4404 | German Werkstoff number |
Relevant Standards – SS 316L Grade
- ASTM A240: Plate, sheet, and strip
- ASTM A276: Bar and shapes
- ASTM A312: Seamless and welded pipe
- ASTM A403: Wrought fittings
- ASTM A182: Flanges and forged fittings
- ASTM A479: Bar for boilers and pressure vessels
- EN 10088-1 / EN 10088-3: Stainless steels – list and technical delivery conditions
- DIN 17440: Stainless steel – plate, strip, bar, wire, forgings
Heat Treatment
- Annealing: Heat to 1010–1120°C and cool rapidly (water quench or rapid air cool) to restore full corrosion resistance and relieve stress.
- Hardening by Heat Treatment: Not possible. Cold working is the only method to increase strength and hardness.
- Stress Relieving: Rarely required due to low sensitisation risk; if performed, cool rapidly through the 425–860°C range.
Fabrication and Weldability
- Machinability: Moderate – rated approximately 45% of AISI 1212. Slow speeds, heavy feeds, sharp tools, and adequate coolant are recommended due to work hardening.
- Formability: Excellent – readily bent, formed, and deep drawn. Work hardens significantly during cold working.
- Weldability: Excellent using GTAW (TIG), GMAW (MIG), SMAW (Stick), FCAW, and SAW processes. No pre-heat or post-weld heat treatment required, making 316L the preferred choice for welded fabrications over standard 316.
Related Grades
| Grade | Relation to 316L |
|---|
| SS 316 | Standard carbon (0.08% max) version; higher strength but more prone to sensitisation when welded |
| SS 316H | Higher carbon (0.04–0.10%) version for improved elevated-temperature strength |
| SS 316Ti | Titanium-stabilised version offering improved resistance to intergranular corrosion at high temperature |
| SS 304 / 304L | Lower-cost austenitic grade without molybdenum; lower chloride/pitting resistance |
| SS 317L | Higher molybdenum (3.0–4.0%) version offering superior pitting resistance |
| SS 904L | Super-austenitic grade with higher Ni, Mo and Cu for severe chloride/acid service |
| Duplex 2205 | Austenitic-ferritic grade with higher strength and superior chloride stress corrosion cracking resistance |
Typical Applications – SS 316L Grade
- Welded pipes, tubes, and pressure vessels for chemical and process industries
- Pharmaceutical and biotech processing equipment, reactors, and piping
- Marine and offshore fittings, fasteners, and hardware
- Food, beverage, and dairy processing equipment
- Medical and surgical instruments and implants
- Desalination and water treatment plant components
- Pulp and paper industry equipment
- Architectural components in coastal or high-chloride environments
- Heat exchangers, condensers, and boiler components
Parts We Can Offer in Stainless Steel 316L
- Tube Fittings (Compression & Push-to-Connect)
- Flanges (WN, SO, Blind, Threaded, Lap Joint, Socket Weld)
- Buttweld Fittings (Elbows, Tees, Reducers, Caps, Stub Ends)
- Threaded Fittings (NPT, BSPT, BSPP)
- Fasteners (Bolts, Nuts, Washers, Studs, Screws)
- Seamless & Welded Pipes and Tubes
- Ball, Gate, and Check Valves
- Investment Castings
- Precision CNC Machined Components
- Sanitary & Hygienic Fittings (Tri-Clamp, Ferrules, Bends)
For technical queries, RFQs, or custom requirements in Stainless Steel 316L Grade (AISI 316L / SUS 316L / EN 1.4404 / UNS S31603), contact us today. Our engineering team is ready to assist with material certifications, mill test reports, and export documentation.
