When working in industries that need strong and corrosion-resistant materials, Duplex stainless steels are a great choice. Among the popular grades, Duplex Steel S31803 Pipe and Duplex Steel S32205 Pipe are often used. Though Duplex Steel S31803, S32205 pipes they are very similar, there are small differences that can affect which one is better for your use.
What is Duplex Stainless Steel?
Duplex stainless steel is a special type of steel that mixes two structures – austenitic and ferritic. This gives it better strength and resistance to corrosion compared to regular stainless steel. It is widely used in oil & gas, chemical plants, water treatment, and marine industries.
About Duplex Steel S31803 Pipe
Duplex Steel S31803 Pipe is one of the early grades of duplex stainless steel. It has a balanced mix of chromium (around 22%), nickel, molybdenum, and nitrogen. This grade offers:
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Good strength
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Excellent resistance to stress corrosion
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Suitable for many industrial uses
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Good weldability and workability
It performs well in environments with mild to moderate corrosion.
About Duplex Steel S32205 Pipe
Duplex Steel S32205 Pipe is an improved version of S31803. It has slightly higher amounts of chromium, molybdenum, and nitrogen. These small changes give S32205:
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Better pitting and crevice corrosion resistance
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Higher yield strength
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Better performance in harsh and chloride-rich conditions
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Greater reliability in aggressive chemical environments
Because of these upgrades, S32205 is often preferred in tougher environments.
Key Differences Between S31803 and S32205
| Property | S31803 | S32205 |
|---|---|---|
| Chromium Content | About 21.0 – 23.0% | About 22.0 – 23.0% |
| Nitrogen Content | Lower than S32205 | Slightly higher |
| Strength | High | Higher than S31803 |
| Corrosion Resistance | Good | Better than S31803 |
| Applications | Standard industrial use | Harsh and corrosive environments |
Where Are These Pipes Used?
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Duplex Steel S31803 Pipe is used in:
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Heat exchangers
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Pressure vessels
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Oil and gas equipment
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Pulp and paper industry
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Duplex Steel S32205 Pipe is used in:
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Marine and offshore platforms
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Desalination plants
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Chemical processing equipment
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Storage tanks in chloride-heavy environments
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Final Thoughts: Which One to Choose?
Both Duplex Steel S31803 Pipe and Duplex Steel S32205 Pipe are strong and reliable. If your job or project involves a normal industrial environment, S31803 is a good option. However, if your application needs higher corrosion resistance and strength, especially near seawater, chemicals, or high pressure, then S32205 is the better choice.
Choosing the right grade helps increase safety, performance, and long life of your system or project. Always consider the working conditions and technical needs before making your decision.
