SUS316L vs SUS304:Key Differences Explained
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SUS304 and SUS316L are two of the most commonly used austenitic stainless steel grades in industrial, architectural, and sanitary applications. While they share many similarities, they differ significantly in corrosion resistance, chemical composition, and suitable environments.
Understanding the key differences can help engineers, procurement professionals, and fabricators select the right material for cost-effective and long-lasting performance.
What is SUS316L Material?
SUS316L is a low-carbon austenitic stainless steel grade in the Japanese JIS standard, equivalent to AISI 316L. It contains 16–18% chromium, 10–14% nickel, and 2–3% molybdenum, which significantly enhances its resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-rich and acidic environments. Its low carbon content (≤0.03%) ensures excellent weldability and intergranular corrosion resistance, making it ideal for marine, pharmaceutical, chemical processing, and cleanroom applications.
What is SUS304 Stainless Steel Material?
SUS304 is an austenitic stainless steel grade under the JIS standard, equivalent to AISI 304. Composed of 18–20% chromium and 8–10.5% nickel, it offers excellent corrosion resistance, good formability, and reliable mechanical strength. SUS304 is widely used in kitchen equipment, food processing, building decoration, and general industrial applications due to its durability, hygienic surface, and affordability. However, it is less resistant to chlorides compared to SUS316L.
Difference between 316L and 304 stainless steel
Chemical Composition Comparison (% by weight)
| Element | SUS304 | SUS316L |
|---|---|---|
| Carbon (C) | ≤ 0.08 | ≤ 0.03 |
| Chromium (Cr) | 18.0 – 20.0 | 16.0 – 18.0 |
| Nickel (Ni) | 8.0 – 10.5 | 10.0 – 14.0 |
| Molybdenum (Mo) | - | 2.0 – 3.0 |
| Manganese (Mn) | ≤ 2.0 | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 | ≤ 1.0 |
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 |
| Sulfur (S) | ≤ 0.03 | ≤ 0.03 |
| Nitrogen (N) | ≤ 0.10 | ≤ 0.10 |
SUS304 and SUS316L stainless steel : corrosion resistance
SUS316L stainless steel contains 2-3% molybdenum and ultra-low carbon (C≤0.03%), and its pitting resistance equivalent (PREN≥32) is higher than that of SUS304 stainless steel (PREN≥28). It has stronger resistance to pitting/crevice corrosion in chloride environments such as seawater, and there is no risk of intergranular corrosion after welding.
SUS316L can withstand 30% sulfuric acid and organic acids at 80°C, while SUS304 is suitable for neutral environments such as food-grade water. In the measured 5% NaCl solution, the crevice corrosion rate of SUS316L is 60% lower than that of SUS304, making it more suitable for chemical, marine and medical applications.
Mechanical Properties (Annealed Condition)
| Property | SUS304 | SUS316L |
|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 485 |
| Yield Strength 0.2% (MPa) | ≥ 205 | ≥ 170 |
| Elongation (%) | ≥ 40 | ≥ 40 |
| Hardness (HRB) | ≤ 90 | ≤ 90 |
| Modulus of Elasticity (GPa) | ~193 | ~193 |
Physical Properties
| Property | SUS304 | SUS316L |
|---|---|---|
| Density (g/cm³) | 7.93 | 7.99 |
| Melting Point (°C) | 1400 – 1450 | 1375 – 1400 |
| Thermal Conductivity (W/m·K) @ 100°C | 16.2 | 16.3 |
| Electrical Resistivity (µΩ·m) | ~0.73 | ~0.74 |
| Specific Heat Capacity (J/kg·K) | 500 | 500 |
| Coefficient of Thermal Expansion (10⁻⁶/K) | 17.2 | 16.0 |
Is SUS316L stronger than SUS304?
SUS316L is generally more corrosion-resistant and durable than SUS304, particularly in high-temperature or chloride-rich environments (like marine, chemical, or pharmaceutical settings). However, in terms of basic tensile strength when annealed, SUS304 is often slightly stronger than 316L.
SUS316L vs SUS304 stainless steel : Cost
SUS316L is typically 20–30% more expensive than SUS304 due to the added molybdenum and nickel content. However, in harsh or corrosive environments, the longer service life and reduced maintenance justify the higher upfront cost.
SUS316L vs. SUS304 Stainless Steel: Applications
SUS316L (the low-carbon variant) exhibits exceptional corrosion resistance-performing particularly well against chlorides and acidic media-making it suitable for applications in marine engineering, chemical processing, and the pharmaceutical sector. SUS304, conversely, is an economical, general-purpose steel grade best suited for food service, architectural decoration, and general non-corrosive environments. Furthermore, 316L offers superior performance in preventing weld corrosion (weld decay).
Need Help Selecting Between SUS304 and SUS316L?
We supply certified SUS304 and SUS316L stainless steel sheets, pipes, and fittings, with custom processing, test reports, and expert consultation.
Certified alloys: AISI 304/304L, 316/316L with guaranteed composition (e.g. Cr 17-19.5%, Ni 8-10%, C ≤0.07%).
Fully Compliant:All products meet South American and European export standards and are certified by ASTM, EN and other relevant certifications.
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