SUS316 vs SUS304 stainless steel: Corrosion resistance
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When selecting stainless steel for industrial applications, understanding the corrosion resistance of various grades is critical to making the right choice. SUS316 and SUS304 are two of the most widely used stainless steel alloys, each with unique properties and suitability for different environments. In this article, we will compare SUS316 vs SUS304 stainless steel in terms of corrosion resistance, helping procurement professionals and engineers make an informed decision for their applications.
What is SUS304 stainless steel?
What is SUS304 stainless steel?
304 grade stainless steel is one of the most commonly used stainless steel alloys, primarily composed of iron, chromium (18-20%), and nickel (8-10%). It offers a good balance of strength, corrosion resistance, and workability. SUS304 is commonly used in food processing, pharmaceuticals, construction, and general applications. However, its corrosion resistance may be limited in harsh environments, especially when exposed to chlorides.
What is SUS316 stainless steel?
316 grade stainless steel contains molybdenum (2-3%) in addition to the core elements found in SUS304. The addition of molybdenum gives SUS316 superior corrosion resistance, particularly in environments where the material will be exposed to chlorides and other corrosive chemicals. Due to its enhanced corrosion resistance and ability to withstand highly corrosive environments, SUS316 is commonly used in marine environments, chemical processing, and medical applications.
SUS316 vs SUS304 stainless steel: Key Differences
SUS316 vs SUS304 stainless steel: Chemical Composition
| Element | SUS304 Stainless Steel | SUS316 Stainless Steel |
|---|---|---|
| Nickel (Ni) | 8.0–10.5% | 10.0–14.0% |
| Chromium (Cr) | 18.0–20.0% | 16.0–18.0% |
| Molybdenum (Mo) | Not present | 2.0–3.0% |
| Carbon (C) | ≤ 0.08% | ≤ 0.08% |
| Manganese (Mn) | 2.0% max | 2.0% max |
| Silicon (Si) | 1.0% max | 1.0% max |
| Phosphorus (P) | 0.045% max | 0.045% max |
| Sulfur (S) | 0.03% max | 0.03% max |
| Iron (Fe) | Balance | Balance |
| Nitrogen (N) | 0.10% max | 0.10% max |
SUS316 vs SUS304 stainless steel:Mechanical Properties
| Property | SUS304 Stainless Steel | SUS316 Stainless Steel |
|---|---|---|
| Tensile Strength (MPa) | 520–720 MPa | 520–720 MPa |
| Yield Strength (MPa) | 215 MPa min | 290 MPa min |
| Elongation (%) | 40% min | 40% min |
| Hardness (HRB) | 90 max | 92 max |
| Modulus of Elasticity (GPa) | 193 GPa | 193 GPa |
| Poisson's Ratio | 0.29 | 0.30 |
| Density (g/cm³) | 7.90 | 7.98 |
| Melting Point (°C) | 1400–1450°C | 1375–1400°C |
| Thermal Conductivity (W/m·K) | 16.2 W/m·K | 16.3 W/m·K |
| Specific Heat (J/g·K) | 0.50 J/g·K | 0.50 J/g·K |
SUS316 vs SUS304 stainless steel: Corrosion resistance
SUS304 has limited resistance to chloride-induced corrosion and is susceptible to pitting and crevice corrosion when exposed to seawater or chloride-containing environments. In such conditions, SUS304 will degrade over time and is therefore unsuitable for marine environments or other areas with high chloride concentrations. However, SUS316 contains molybdenum, which gives it superior resistance to pitting and crevice corrosion in chloride-rich environments. Therefore, SUS316 is the preferred material for applications where chloride corrosion is a concern, such as marine applications, swimming pools, and chemical plants.
| Property | SUS304 Stainless Steel | SUS316 Stainless Steel |
|---|---|---|
| Corrosion Resistance | Good resistance to oxidation, but limited in chloride and acidic environments | Superior resistance to chloride, acid, and pitting corrosion |
| Chloride Resistance | Susceptible to pitting in high-chloride environments | Excellent resistance to pitting and crevice corrosion in chloride-rich environments |
| Acid Resistance | Moderate resistance to sulfuric and acetic acid | Higher resistance to sulfuric, hydrochloric, and acetic acids |
| Oxidation Resistance | Up to 870°C (1600°F) | Up to 925°C (1700°F) |
How do SUS304 and SUS316 perform at high temperatures?
SUS304 can resist oxidation at temperatures up to 870°C (1600°F), whereas SUS316 offers better performance at higher temperatures, up to 925°C (1700°F), due to the molybdenum content.
What are the typical applications for SUS316?
SUS316 is used in industries where corrosion resistance is crucial, including marine environments, chemical processing, pharmaceuticals, and medical devices. It is also used in high-temperature applications like heat exchangers and boilers.
Why is SUS316 more expensive than SUS304?
SUS316 is more expensive than SUS304 due to the addition of molybdenum, which significantly improves its corrosion resistance and strength in harsh environments. The increased cost is justified by its enhanced performance in demanding applications.
SUS316 and SUS304 stainless steel Suppliers
If you have project requirements for 1.4547 stainless steel, we welcome your order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com
Testing and Documentation: Factory test certificate, EN 10204 3.1, chemical report, mechanical report, destructive testing report, non-destructive testing report, PMI test report, visual inspection report, third-party inspection report, NABL certified laboratory report.
Packaging: Wooden crate packaging, bubble wrap packaging, steel strapping, or packaging according to customer requirements.
