What is the difference between SS 309 and 304 stainless steel?
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Chemical composition:
304 stainless steel: mainly composed of chromium and nickel, without molybdenum, chromium content of 18%-20%, nickel content of 8%-10.5%.
309 stainless steel: chromium and nickel content are higher than 304, and contains a small amount of molybdenum, which increases its special properties.
Corrosion resistance:
304 stainless steel: performs well in general environment, but corrosion resistance may be reduced in chloride ion or acidic environment.
309 stainless steel: has excellent corrosion resistance, especially suitable for high temperature and high corrosion environment.
High temperature performance:
304 stainless steel: suitable for general high temperature environment, but high temperature performance is relatively limited.
309 stainless steel: mainly used in high temperature application scenarios, such as chemical industry, electric power and other fields, can maintain stable performance and strength at high temperature.
Application field:
304 is widely used in construction, furniture and other fields; 309 is mainly used in high temperature equipment, heat exchangers and other fields that require high temperature resistance.
| Aspect | SS 304 | SS 309 |
|---|---|---|
| Chemical Composition | - Cr: 18%-20% - Ni: 8%-10.5% - C: ≤0.08% - Mo: None |
- Cr: Higher than 304 - Ni: Higher than 304 - C: ≤0.18% (or ≤0.08% in some cases) - Mo: Small amount |
| Mechanical Properties | - Tensile Strength: ≥520 MPa - Yield Strength: ≥205 MPa - Elongation: ≥40% |
- Tensile Strength: ≈520 MPa - Yield Strength: ≈205 MPa - Elongation: ≈40% - Higher strength at high temperatures |
