Stainless Steel 316 Grade
Stainless Steel 316 Grade is a molybdenum-bearing austenitic stainless steel. The addition of molybdenum (2–3%) significantly enhances its corrosion resistance compared to Grade 304, especially against chlorides, industrial solvents, and marine environments. It is one of the most widely used stainless steel grades in chemical processing, marine, food & beverage, pharmaceutical, and oil & gas industries.
International Equivalent Designations – Stainless Steel 316 Grade
Stainless Steel 316 Grade is known by several designations depending on the country and standard. The table below lists all major international equivalents:
| Standard / Country | Designation | Description |
|---|
| AISI / ASTM (USA) | AISI 316 / SS 316 | American Iron and Steel Institute designation |
| UNS (USA) | UNS S31600 | Unified Numbering System |
| EN / DIN (Europe) | 1.4401 | European material number (Werkstoff-Nr.) |
| EN Short Name (Europe) | X5CrNiMo17-12-2 | European chemical composition designation |
| JIS (Japan) | SUS 316 | Japanese Industrial Standard |
| BS (United Kingdom) | 316 S 31 | British Standard designation |
| GB (China) | 0Cr17Ni12Mo2 | Chinese national standard |
| ISO | X5CrNiMo17-12-2 | International Organization for Standardization |
| AFNOR (France) | Z6CND17-11 | French standard designation |
| SS (Sweden) | 2347 | Swedish standard designation |
Chemical Composition (Weight %)
| Element | Min % | Max % |
|---|
| Carbon (C) | – | 0.08 |
| Manganese (Mn) | – | 2.00 |
| Silicon (Si) | – | 0.75 |
| Phosphorus (P) | – | 0.045 |
| Sulphur (S) | – | 0.030 |
| Chromium (Cr) | 16.00 | 18.00 |
| Nickel (Ni) | 10.00 | 14.00 |
| Molybdenum (Mo) | 2.00 | 3.00 |
| Nitrogen (N) | – | 0.10 |
| Iron (Fe) | Balance |
Mechanical Properties (Annealed Condition – Room Temperature)
| Property | Value | Unit |
|---|
| Tensile Strength (UTS) | 515 min | MPa (74,700 psi) |
| Yield Strength (0.2% Proof) | 205 min | MPa (29,700 psi) |
| Elongation (in 50 mm) | 40 min | % |
| Hardness – Brinell | 217 max | HB |
| Hardness – Rockwell B | 95 max | HRB |
| Hardness – Vickers | 220 max | HV |
| Elastic Modulus | 193 | GPa |
| Poisson’s Ratio | 0.27 – 0.30 | – |
Physical Properties
| Property | Value | Unit |
|---|
| Density | 8.0 | g/cm³ |
| Melting Range | 1371 – 1399 | °C (2500 – 2550 °F) |
| Specific Heat Capacity (0–100°C) | 500 | J/kg·K |
| Thermal Conductivity (at 100°C) | 16.2 | W/m·K |
| Thermal Expansion Coefficient (0–100°C) | 15.9 × 10⁻⁶ | /°C |
| Electrical Resistivity (at 20°C) | 74 | µΩ·cm |
| Magnetic Permeability | 1.008 max | Non-magnetic (annealed) |
Elevated Temperature Mechanical Properties
| Temperature (°C) | Tensile Strength (MPa) | 0.2% Yield Strength (MPa) |
|---|
| 200 | 460 | 150 |
| 400 | 420 | 130 |
| 600 | 350 | 120 |
| 800 | 190 | 110 |
Corrosion Resistance
Stainless Steel 316 Grade offers superior corrosion resistance due to its molybdenum content. Key characteristics include:
- Pitting and Crevice Corrosion: Molybdenum significantly improves resistance to pitting in chloride-containing environments compared to Grade 304.
- General Corrosion: Excellent resistance to most oxidising and mildly reducing environments including dilute sulphuric acid, acetic acid, and phosphoric acid.
- Marine Environments: Suitable for use in marine and coastal environments where chloride exposure is significant.
- Sensitisation: Can be sensitised in the 425–860°C range; in such applications Grade 316L (low carbon, 1.4404) is recommended.
- Stress Corrosion Cracking (SCC): Susceptible to SCC in high-chloride environments above 50°C; duplex grades are preferable in severe conditions.
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: Not recommended due to risk of sensitisation; if required, cool rapidly through the 425–860°C sensitisation range.
Fabrication and Weldability
- Machinability: Moderate – rated approximately 60% of AISI 1212. Slow speeds, heavy feeds, and sharp tools recommended.
- Formability: Excellent – can be readily bent, drawn, and formed. Work hardens significantly during cold working.
- Weldability: Excellent using GTAW (TIG), GMAW (MIG), SMAW (Stick), FCAW, and resistance welding. No pre-heat required.
- Recommended Filler Metal: ER316L or E316L-16 to prevent weld decay and intergranular corrosion.
- Post-Weld Treatment: Solution annealing recommended for maximum corrosion resistance in critical applications.
Related Sub-Grades of Stainless Steel 316 Grade
| Grade | AISI / UNS | EN / DIN | JIS | Key Difference |
|---|
| 316L | AISI 316L / S31603 | 1.4404 / X2CrNiMo17-12-2 | SUS 316L | Low carbon (≤0.03%) – better intergranular corrosion resistance after welding |
| 316H | AISI 316H / S31609 | 1.4919 | SUS 316H | Higher carbon (0.04–0.10%) – improved high-temperature creep strength |
| 316Ti | S31635 | 1.4571 / X6CrNiMoTi17-12-2 | SUS 316Ti | Titanium-stabilised – resists sensitisation, suitable for continuous high-temperature service |
| 316N | S31651 | 1.4406 | – | Nitrogen-enhanced – higher strength without reduction in corrosion resistance |
| 316LN | S31653 | 1.4429 | SUS 316LN | Low carbon + nitrogen – combines weldability and higher strength |
Applicable Standards & Specifications
| Standard | Scope |
|---|
| ASTM A240 / A240M | Sheet, strip, and plate for pressure vessels and general applications |
| ASTM A276 / A276M | Stainless steel bars and shapes |
| ASTM A312 / A312M | Seamless and welded austenitic stainless steel pipes |
| ASTM A182 / A182M | Forged or rolled pipe flanges, fittings, and valves (F316) |
| ASTM A479 / A479M | Stainless steel bars for boilers and pressure vessels |
| ASME SA-240 | Pressure vessel plate (ASME equivalent of A240) |
| EN 10088-2 | Stainless steels – sheet, plate, and strip (1.4401) |
| EN 10088-3 | Stainless steels – semi-finished products, bars, rods (1.4401) |
| JIS G4303 | Stainless steel bars – SUS 316 |
| JIS G4304 | Hot-rolled stainless steel plate, sheet and strip – SUS 316 |
| ISO 15510 | Stainless steels – chemical composition |
Typical Applications
Stainless Steel 316 Grade / 1.4401 / SUS 316 is used across a wide range of demanding industries:
- Chemical & Petrochemical: Pressure vessels, heat exchangers, reaction vessels, chemical storage tanks, piping systems
- Marine & Offshore: Boat fittings, propeller shafts, marine hardware, offshore platform structural components
- Food & Beverage: Processing equipment, brewing tanks, dairy equipment, food-grade fittings and valves
- Pharmaceutical: Reactors, bioreactors, sterile fittings, clean-room equipment, sanitary valves
- Oil & Gas: Subsea fittings, tubing, flanges, heat exchanger tubes
- Medical: Surgical instruments, implants, medical devices
- Architectural: Exterior cladding, handrails, fasteners in coastal buildings
- Textile: Dyeing and bleaching equipment
- Pulp & Paper: Digesters, bleaching equipment, pipeline components
Supply Forms – Stainless Steel Fittings India (SSF)
At Stainless Steel Fittings India (SSF), we manufacture and export Stainless Steel 316 Grade / AISI 316 / 1.4401 / SUS 316 components in the following forms:
- Pipe Fittings (Elbows, Tees, Reducers, Caps, Crosses)
- Tube Fittings (Compression & Push-to-Connect)
- Flanges (WN, SO, Blind, Threaded, Lap Joint, Socket Weld)
- Threaded Fittings (NPT, BSPT, BSPP)
- Fasteners (Bolts, Nuts, Washers, Studs, Screws)
- Investment Castings
- Precision Machined Components
- Sanitary & Hygienic Fittings
For technical queries, RFQs, or custom requirements in Stainless Steel 316 Grade (AISI 316 / SUS 316 / 1.4401 / UNS S31600), contact us today. Our engineering team is ready to assist with material certifications, mill test reports, and export documentation.
