If you need a stainless steel that thrives in harsh environments—like seawater, chemicals, or high heat—JIS SUS316 stainless steel is the gold standard. It’s more corrosion-resistant than the common SUS304, thanks to extra molybdenum, making it a top choice for marine, pharmaceutical, and industrial projects. This guide breaks down everything you need to know to use it effectively.
1. Material Properties of JIS SUS316 Stainless Steel
JIS SUS316 stainless steel owes its performance to its unique material properties—from its alloy makeup to its mechanical strength. Let’s dive in:
Alloy Composition
The key to its corrosion resistance is molybdenum, a component missing in basic SUS304. Here’s the detailed breakdown:
| Element | Content Range | Role in Performance |
|---|---|---|
| Chromium | 16.0% – 18.0% | Forms a protective oxide layer (fights rust and pitting) |
| Nickel | 10.0% – 14.0% | Stabilizes the austenitic structure (boosts ductility and toughness) |
| Molybdenum | 2.0% – 3.0% | Enhances resistance to chlorides (critical for seawater and chemicals) |
| Carbon | ≤0.08% | Maintains strength without increasing corrosion risk |
| Manganese | ≤2.0% | Improves workability during manufacturing (e.g., rolling, welding) |
Mechanical & Physical Properties
It balances strength and flexibility, making it suitable for diverse projects. Here’s how it performs:
| Property | Typical Value (Annealed) | Practical Benefit |
|---|---|---|
| Mechanical Strength (Tensile) | 515 MPa | Handles high pressure (ideal for chemical pipes or marine shafts) |
| Yield Strength | 205 MPa | Resists bending (great for structural parts like offshore brackets) |
| Elongation | ≥40% | Bends and stretches without cracking (perfect for curved marine parts) |
| Hardness | ≤210 HB (Brinell) | Soft enough for machining, yet durable against scratches |
| Density | 8.0 g/cm³ | Slightly denser than SUS304 (adds stability for heavy-duty parts) |
| Thermal Conductivity | 16.2 W/m·K (at 100°C) | Transfers heat evenly (suitable for heat exchangers in chemical plants) |
| Electrical Conductivity | 1.3 x 10⁶ S/m | Lower than copper (good for parts needing electrical insulation) |
| Magnetic Properties | Non-magnetic | Won’t stick to magnets (unlike ferritic steels like SUS430) |
A marine engineering firm in Japan uses SUS316 for propeller shafts. Its high tensile strength (515 MPa) withstands the torque of spinning propellers, while its non-magnetic property avoids interfering with navigation equipment.
2. Applications of JIS SUS316 Stainless Steel
Thanks to its corrosion resistance, JIS SUS316 stainless steel is used in industries where failure is not an option. Here are its top applications:
- Marine Applications: Ship hulls, propeller shafts, and offshore platforms. A shipyard in South Korea builds coastal patrol vessels with SUS316 hulls—no rust after 5 years in saltwater.
- Chemical Processing Plants: Pipes, reactors, and storage tanks for acids (e.g., sulfuric acid) and solvents. A chemical firm in Germany uses SUS316 for nitric acid tanks—no corrosion or leaks for 8 years.
- Pharmaceutical Equipment: Drug manufacturing tanks and sterile conveyors. It meets strict purity standards (e.g., FDA) and resists cleaning chemicals. A Swiss pharma company uses it for vaccine mixing tanks—no metal leaching into products.
- Food Processing Equipment: Seafood processing machines and saltwater-based cleaning systems. A fish cannery in Norway uses SUS316 for conveyor belts—resists saltwater and fish oils.
- Aerospace Components: Engine parts and fuel lines (handles high heat and jet fuels). An aerospace supplier in the U.S. uses SUS316 for fuel connectors—withstands temperatures up to 600°C.
- Sanitary Fittings: Hospital faucets and lab sinks (easy to sterilize and resists disinfectants). A Singapore hospital uses SUS316 for operating room sinks—no corrosion from daily bleach cleaning.
3. Manufacturing Processes for JIS SUS316 Stainless Steel
JIS SUS316 stainless steel is versatile to manufacture, though its molybdenum content requires slight adjustments compared to SUS304. Here are the key manufacturing processes:
- Hot Rolling: Heated to 1100–1200°C and rolled into thick plates, bars, or pipe blanks. Used for large parts like marine propeller shafts. A steel mill in China uses hot rolling for SUS316 bars—ensures uniform strength.
- Cold Rolling: Done at room temperature to make thin sheets (e.g., aerospace parts) or precise components. Improves surface smoothness—critical for pharmaceutical equipment.
- Annealing: Heated to 1050–1150°C and quenched in water. Softens the steel after cold working (e.g., bending) and restores corrosion resistance. A fabricator anneals SUS316 sheets before forming them into lab sinks—prevents cracking.
- Pickling: Treated with nitric acid to remove scale (from rolling or welding). Enhances the oxide layer—key for marine parts. A shipyard pickles SUS316 hull plates before painting—ensures no rust under the coating.
- Machining: Drilled, milled, or turned with high-speed steel (HSS) or carbide tools. Use coolant to avoid overheating (molybdenum can make it slightly harder to machine than SUS304). A machine shop uses carbide tools to make SUS316 valve parts—achieves tight tolerances.
- Forming: Deep drawing (for sinks), bending (for trim), and extrusion (for pipes) are all possible, thanks to its high elongation (≥40%). A sink manufacturer deep-draws SUS316 into seamless marine sinks—no leaks.
4. Corrosion Resistance of JIS SUS316 Stainless Steel
The biggest advantage of JIS SUS316 stainless steel is its exceptional corrosion resistance—it outperforms most stainless steels in harsh conditions:
- Pitting Resistance: Molybdenum prevents small holes (pitting) in chlorides. Tests show it resists pitting in 3.5% saltwater (simulating seawater) at temperatures up to 80°C—SUS304 fails at 60°C.
- Crevice Corrosion: Performs well in tight spaces (e.g., bolted joints) if cleaned regularly. A marine engineer tested SUS316 in crevices filled with seawater—no corrosion after 18 months.
- Intergranular Corrosion: Low carbon content (≤0.08%) prevents cracking in high heat (e.g., chemical reactors at 500°C). A refinery uses SUS316 for heated fuel lines—no issues for 6 years.
- Stress Corrosion Cracking (SCC): Resists SCC in chlorides and acids. A pharmaceutical plant uses SUS316 for pressure vessels holding acidic drugs—no cracking under 100 bar pressure.
- Surface Treatment for Extra Protection: Passivation (treating with nitric acid) thickens the oxide layer. A lab passivates SUS316 equipment—extends its life by 4x.
It’s not invincible (avoid concentrated hydrochloric acid), but it’s the best choice for most chloride-rich or chemical-heavy environments.
5. Welding JIS SUS316 Stainless Steel
JIS SUS316 stainless steel has good weldability, but you need to match the filler to its molybdenum content. Here’s how to do it right:
- Welding Processes: TIG (Tungsten Inert Gas) is best for thin parts (e.g., lab pipes), while MIG (Metal Inert Gas) works for thicker sections (e.g., marine brackets). A welder in Australia uses TIG for SUS316 pharmaceutical pipes—creates clean, leak-proof welds.
- Welding Rods: Use molybdenum-rich fillers like AWS ER316L (low carbon) or ER316. Avoid SUS304 fillers—they lack molybdenum, leading to corrosion in the weld. A shipyard once used ER308 (SUS304 filler)—the weld rusted in 3 months.
- Welding Gases: Use argon (for TIG) or argon-2% CO₂ (for MIG) to protect the weld from oxygen. This prevents oxidation and weak spots.
- Post-Weld Heat Treatment: Not always needed, but annealing at 1050–1150°C removes stress (critical for load-bearing parts like offshore shafts). A structural fabricator anneals SUS316 welds—ensures no cracking under wave pressure.
- Welding Inspection: Use X-ray or ultrasonic testing for critical parts (e.g., chemical reactors). A quality control team tests SUS316 welds—catches tiny defects before they cause leaks.
- Welding Safety: Wear a heat-resistant jacket and welding helmet—SUS316 produces intense sparks during welding.
6. Standards and Specifications for JIS SUS316 Stainless Steel
To ensure quality, JIS SUS316 stainless steel follows strict global standards. Here’s what you need to know:
- JIS G4304: The Japanese Industrial Standard for hot-rolled stainless steel plates, sheets, and strips (covers SUS316’s dimensions and composition).
- ASTM A240: The U.S. standard (ASTM A240 Type 316 is equivalent to JIS SUS316)—you can use them interchangeably.
- EN 10088: The European standard (EN 10088-2 X5CrNiMo17-12-2 is the equivalent grade).
- ISO Standards: ISO 15510 specifies its chemical composition and mechanical properties for global projects.
- Material Certification: Ask for a Mill Test Certificate (MTC) to verify compliance. A marine client requires MTCs for all SUS316 parts—ensures they meet seawater resistance standards.
- Quality Control: Manufacturers test for molybdenum content, corrosion resistance, and tensile strength. A steel supplier rejects batches of SUS316 with less than 2.0% molybdenum—they won’t perform in seawater.
7. Comparison with Other Materials
How does JIS SUS316 stainless steel stack up against other common materials? Here’s a clear breakdown:
| Material | Key Advantage vs. SUS316 | Key Disadvantage vs. SUS316 | Best For |
|---|---|---|---|
| SUS304 | Lower cost (~20% cheaper) | Poor chloride resistance | Indoor applications (e.g., kitchen sinks) |
| SUS316L | Better intergranular corrosion resistance (low carbon) | Slightly lower strength | High-heat chemical reactors |
| Carbon Steel | Much cheaper (~50% lower) | No corrosion resistance | Indoor structural parts (e.g., beams) |
| Duplex Stainless Steel | Higher strength | Less ductile (harder to form) | High-pressure oil pipes |
| Titanium Alloys | Extreme corrosion resistance | Very expensive (~5x cost) | Deep-sea equipment, aerospace parts |
| Aluminum Alloys | Lighter (density 2.7 g/cm³) | Less strong (tensile 276 MPa) | Lightweight parts (e.g., bike frames) |
For marine, chemical, or pharmaceutical projects, SUS316 offers the best balance of performance and cost—beating SUS304 in harsh conditions and titanium in affordability.
Yigu Technology’s Perspective on JIS SUS316 Stainless Steel
At Yigu Technology, JIS SUS316 is our top recommendation for clients in marine, chemical, and pharmaceutical sectors. Its molybdenum-enhanced corrosion resistance solves their biggest pain point: frequent equipment replacement due to rust or chemical damage. We help clients optimize welding (using ER316 fillers) and manufacturing to maximize its lifespan—whether it’s for offshore platforms or sterile drug tanks. While SUS316 costs more than SUS304, its 2–3x longer service life makes it a cost-effective choice long-term.
FAQ About JIS SUS316 Stainless Steel
- Is JIS SUS316 better than SUS304 for outdoor use?
Yes—especially in coastal areas. SUS316’s molybdenum makes it resistant to saltwater spray, while SUS304 may rust within 2–3 years near the ocean. For inland outdoor use, SUS304 is cheaper, but SUS316 lasts longer. - Can JIS SUS316 be used in food processing?
Absolutely! It meets FDA and JIS Z 2801 food safety standards. It’s ideal for seafood processing (resists saltwater) or acidic food production (e.g., tomato sauce)—unlike SUS304, it won’t corrode from food acids. - Is JIS SUS316 hard to machine?
It’s slightly harder to machine than SUS304 (due to molybdenum), but manageable. Use carbide tools (instead of HSS) and plenty of coolant to avoid overheating. A machine shop can achieve precise cuts with the right tools—no extra effort needed.
