430 stainless steel vs 304: Corrosion resistance
Jul 04, 2025
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When selecting stainless steel for your project, one of the most important factors is corrosion resistance. Two commonly used grades are 430 and 304 stainless steel, but they differ significantly in terms of alloy composition, resistance in various environments, and long-term durability.
What is the Difference Between SAE 304 and SAE 430?
SAE 304 is an austenitic stainless steel containing 18-20% chromium and 8-10.5% nickel. It has a face-centered cubic structure and is non-magnetic at room temperature. It can be widely used in food equipment, medical equipment and corrosion-resistant structural parts.
SAE 430 is a ferritic stainless steel containing 16-18% chromium and almost no nickel. It has a body-centered cubic structure and is magnetic. Its corrosion resistance is weaker than 304, but it has good thermal conductivity, low thermal expansion coefficient, and lower cost. It is mostly used in decorative parts, home appliance housings and automotive exhaust systems that do not require high corrosion resistance.
430 vs 304 Stainless Steel:Chemical Composition
| Element | 430 Stainless Steel (% by weight) | 304 Stainless Steel (% by weight) |
|---|---|---|
| Carbon (C) | ≤ 0.12 | ≤ 0.08 |
| Manganese (Mn) | ≤ 1.00 | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.04 | ≤ 0.045 |
| Sulfur (S) | ≤ 0.03 | ≤ 0.03 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 |
| Chromium (Cr) | 16.00 – 18.00 | 18.00 – 20.00 |
| Nickel (Ni) | ≤ 0.75 (typically none) | 8.00 – 10.50 |
| Nitrogen (N) | – | ≤ 0.10 |
430 vs 304 Stainless Steel: Corrosion Resistance
In terms of corrosion resistance, 304 austenitic stainless steel, with its alloy ratio of 8-10.5% nickel and 18-20% chromium, is significantly better than 430 ferritic stainless steel (16-18% chromium, no nickel) in a variety of corrosive environments.
Specific data show that the pitting potential of 304 is as high as + 250 mV (SCE), which is 150 mV higher than the + 100 mV of 430, which means that it is less prone to pitting in chloride environments. In the salt spray test, ordinary SUS430 substrates only rusted after 40 hours, while SUS304VJ substrates can withstand 250 hours; according to ASTM B117 standard, the annual corrosion rate of 304 is only 0.03 mm/year, which is much lower than the performance of 430 under similar conditions.
However, 430 can still meet basic requirements in dry atmosphere or neutral aqueous solution. Its cost is 20-30% lower than 304, and it is suitable for scenarios such as home appliance casings and interior decoration with lower corrosion resistance requirements.
Looking for the Right Stainless Steel Supplier?
At Gnee Steel, we supply both 430 and 304 stainless steel sheets, coils, and tubes, available in various surface finishes like 2B, BA, No.4, and mirror polish - with full certification and quality inspection.
🔹 In-stock delivery & custom dimensions
🔹 ISO 9001 + SGS/BV test reports
🔹 Global export services with secure packaging
📩 Contact our team for technical advice or to request a quote - we help you choose the right stainless steel for your environment and budget.
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