Overview
SS316 (AISI 316 Stainless Steel) is a molybdenum-bearing austenitic stainless steel belonging to the 300 Series Stainless Steel Family. It is widely recognized for its exceptional corrosion resistance, particularly in chloride-rich and marine environments.
The addition of 2–3% molybdenum (Mo) significantly improves resistance to pitting, crevice corrosion, and chemical attack compared with SS304. As a result, SS316 is commonly referred to as Marine Grade Stainless Steel and is extensively used in marine engineering, chemical processing, pharmaceutical manufacturing, medical devices, food processing, offshore equipment, and architectural applications.
Compared with SS304, SS316 offers superior corrosion resistance but at a higher material cost.
Material Specification
| Property | Value |
|---|---|
| Material Designation | AISI 316 |
| Material Family | Austenitic Stainless Steel |
| UNS Number | S31600 |
| EN Grade | 1.4401 |
| Density | 8.00 g/cm³ |
| Magnetic Property | Non-Magnetic (Annealed), Slightly Magnetic After Cold Working |
| Standard Forms | Sheet, Plate, Coil, Pipe, Tube, Bar, Wire |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Chromium (Cr) | 16.0–18.0 |
| Nickel (Ni) | 10.0–14.0 |
| Molybdenum (Mo) | 2.0–3.0 |
| Carbon (C) | ≤0.08 |
| Manganese (Mn) | ≤2.00 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.045 |
| Sulfur (S) | ≤0.030 |
| Nitrogen (N) | ≤0.10 |
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | ≥515 MPa |
| Yield Strength | ≥205 MPa |
| Elongation | ≥40% |
| Hardness | ≤95 HRB |
| Elastic Modulus | 193 GPa |
| Fatigue Strength | 240 MPa |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.00 g/cm³ |
| Melting Point | 1375–1400°C |
| Thermal Conductivity | 16.3 W/m·K |
| Electrical Resistivity | 0.74 μΩ·m |
| Thermal Expansion Coefficient | 16.0 × 10⁻⁶/K |
| Specific Heat Capacity | 500 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Atmospheric Exposure | Excellent |
| Industrial Environment | Excellent |
| Marine Environment | Outstanding |
| Salt Spray Environment | Outstanding |
| Chloride Environment | Excellent |
| Chemical Processing Environment | Excellent |
| Food Processing Environment | Excellent |
SS316 offers excellent resistance to:
- Chloride Pitting Corrosion
- Crevice Corrosion
- Saltwater Exposure
- Acidic Solutions
- Chemical Processing Media
This makes SS316 one of the most versatile corrosion-resistant stainless steels available.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | 316 |
| UNS | S31600 |
| EN (Europe) | 1.4401 |
| DIN (Germany) | X5CrNiMo17-12-2 |
| JIS (Japan) | SUS316 |
| GB/T (China) | 06Cr17Ni12Mo2 |
| ISO | X5CrNiMo17-12-2 |
Available Forms
| Product Type | Availability |
|---|---|
| Stainless Steel Sheet | Yes |
| Stainless Steel Plate | Yes |
| Stainless Steel Coil | Yes |
| Stainless Steel Pipe | Yes |
| Stainless Steel Tube | Yes |
| Stainless Steel Bar | Yes |
| Stainless Steel Wire | Yes |
| Forgings | Yes |
Typical Applications
Marine Industry
- Boat Hardware
- Marine Fasteners
- Offshore Platforms
- Ship Components
- Yacht Equipment
Chemical Processing Industry
- Chemical Storage Tanks
- Reactors
- Pumps
- Valves
- Process Piping
Pharmaceutical Industry
- Pharmaceutical Equipment
- Sterile Processing Systems
- Cleanroom Components
- Medical Containers
Food & Beverage Industry
- Food Processing Equipment
- Brewing Systems
- Dairy Equipment
- Beverage Production Lines
Medical Industry
- Surgical Instruments
- Implant Components
- Medical Devices
- Laboratory Equipment
Architectural Industry
- Coastal Building Structures
- Exterior Cladding
- Handrails
- Decorative Components
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| Laser Cutting | Excellent |
| Waterjet Cutting | Excellent |
| CNC Machining | Good |
| Stamping | Excellent |
| Deep Drawing | Excellent |
| Bending | Excellent |
| TIG Welding | Excellent |
| MIG Welding | Excellent |
| Laser Welding | Excellent |
| Polishing | Excellent |
Advantages
Outstanding Corrosion Resistance
Superior performance in marine and chemical environments.
Excellent Chloride Resistance
Resists pitting and crevice corrosion.
Excellent Weldability
Compatible with all major welding methods.
Hygienic Surface
Ideal for medical, pharmaceutical, and food-grade applications.
Excellent Mechanical Properties
Combines corrosion resistance with good strength.
Long Service Life
Reduces maintenance and replacement costs.
Limitations
Higher Cost Than SS304
Due to molybdenum content.
Work Hardening During Machining
Requires optimized machining parameters.
Lower Thermal Conductivity
Compared with aluminum and copper.
Not Designed for Extreme High-Temperature Service
SS309 or SS310 may be preferred for continuous exposure above 900°C.
Comparison with Other Stainless Steels
| Property | SS316 | SS304 | SS316L | SS2205 Duplex | SS321 |
|---|---|---|---|---|---|
| Corrosion Resistance | Outstanding | Excellent | Outstanding | Excellent | Excellent |
| Chloride Resistance | Excellent | Moderate | Excellent | Outstanding | Moderate |
| Marine Applications | Excellent | Good | Excellent | Outstanding | Fair |
| Weldability | Excellent | Excellent | Outstanding | Good | Excellent |
| Strength | Medium | Medium | Medium | High | Medium |
| Cost | High | Medium | High | High | High |
Comparison with Common Engineering Metals
| Material | Density (g/cm³) | Corrosion Resistance | Marine Use | Strength |
|---|---|---|---|---|
| SS316 | 8.00 | Outstanding | Excellent | Medium |
| SS304 | 8.00 | Excellent | Good | Medium |
| Aluminum 5083 | 2.66 | Excellent | Excellent | Medium |
| Titanium Grade 2 | 4.51 | Outstanding | Outstanding | Medium |
| Carbon Steel A36 | 7.85 | Poor | Poor | Medium |
| Duplex 2205 | 7.80 | Outstanding | Outstanding | High |
Available Surface Finishes
Mill Finishes
- No.1 Finish
- 2B Finish
- BA (Bright Annealed)
- No.4 Finish
Decorative Finishes
- Mirror Polish (8K)
- Hairline Finish
- Satin Finish
- Vibration Finish
- Brushed Finish
- Sandblasted Finish
- Etched Finish
Functional Finishes
- Passivation
- Electropolishing
- Anti-Fingerprint Coating
- PVD Coating
Frequently Asked Questions (FAQ)
What is SS316 stainless steel?
SS316 is a molybdenum-containing stainless steel designed for superior corrosion resistance, especially in marine and chloride-rich environments.
What is SS316 used for?
Typical applications include:
- Marine Equipment
- Offshore Structures
- Chemical Processing Systems
- Pharmaceutical Equipment
- Food Processing Equipment
- Medical Devices
Is SS316 food grade?
Yes. SS316 is widely used in food, beverage, pharmaceutical, and medical industries.
What is the difference between SS304 and SS316?
| Property | SS304 | SS316 |
|---|---|---|
| Molybdenum | No | 2–3% |
| Chloride Resistance | Moderate | Excellent |
| Marine Applications | Limited | Recommended |
| Cost | Lower | Higher |
Is SS316 marine grade stainless steel?
Yes. SS316 is commonly referred to as marine-grade stainless steel because of its superior resistance to seawater and salt spray environments.
Can SS316 rust?
Under normal service conditions, SS316 has excellent corrosion resistance. However, contamination, poor maintenance, or extreme chemical exposure can still cause localized corrosion.
Is SS316 suitable for outdoor coastal applications?
Yes. SS316 is one of the preferred materials for coastal architecture and marine structures.
Can SS316 be welded?
Yes. SS316 provides excellent weldability using TIG, MIG, laser, and resistance welding processes.
Why is SS316 used in pharmaceutical equipment?
Because it combines:
- Excellent Corrosion Resistance
- Hygienic Surface Finish
- Easy Cleaning
- Chemical Resistance
- Regulatory Compliance
making it ideal for pharmaceutical and medical applications.
Does GCNOV provide custom manufacturing services for SS316?
Yes. GCNOV provides:
- CNC Machining
- Laser Cutting
- Sheet Metal Fabrication
- Tube Fabrication
- TIG & MIG Welding
- Electropolishing
- Passivation
- Mirror Polishing
- Prototype Development
- Low-Volume Production
- Mass Production