Description
Alloy Geek 321 Austenitic Stainless Steel Standard
Alloy 321, also known as AISI 321 or UNS S32100, is a stabilized austenitic stainless steel alloy that contains titanium. The addition of titanium provides several benefits, including improved resistance to sensitization and intergranular corrosion at elevated temperatures. Alloy 321 is often chosen for applications involving high-temperature environments and where resistance to carbide precipitation and sensitization is critical.
The composition of Alloy 321 typically includes:
- Chromium (Cr): 17-19%
- Nickel (Ni): 9-12%
- Titanium (Ti): 5(C+N) (~0.70%)
- Carbon (C): 0.08% max
- Manganese (Mn): 2% max
- Silicon (Si): 0.75% max
- Phosphorus (P): 0.045% max
- Sulfur (S): 0.03% max
- Nitrogen (N): 0.10% max
- Iron (Fe): Remainder
Key features and characteristics of Alloy 321:
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Sensitization Resistance: The titanium stabilization in Alloy 321 prevents the formation of chromium carbides at grain boundaries during heating and cooling, reducing the risk of sensitization and intergranular corrosion.
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High-Temperature Performance: Alloy 321 retains its mechanical properties, strength, and corrosion resistance at elevated temperatures, making it suitable for applications involving heat and thermal cycling.
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Corrosion Resistance: It offers good general corrosion resistance in a variety of environments, including many acidic and alkaline conditions.
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Weldability: Alloy 321 is easily weldable using common welding methods. The titanium content helps to maintain its corrosion resistance near the welds.
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Applications: It's used in industries such as petrochemical, aerospace, and power generation. Typical applications include heat exchangers, furnace components, and components for exhaust systems.
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Forms: Alloy 321 is available in various forms, including sheets, plates, bars, and pipes.
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Versatility: Alloy 321 is often selected for applications where both high-temperature resistance and sensitization resistance are required.
Alloy 321's titanium stabilization sets it apart by providing enhanced performance at elevated temperatures compared to other standard austenitic stainless steels. Its ability to resist sensitization and intergranular corrosion makes it a reliable choice for applications where exposure to high temperatures is expected, such as in the presence of combustion gases or high-temperature process environments.
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In summary, the main difference between a reference material and a certified reference material lies in the level of characterization, validation, and certification. CRMs have undergone a more comprehensive and rigorous testing process, resulting in certified values and uncertainties that can be confidently used for instrument calibration, quality control, and research. Reference materials, on the other hand, can provide a point of comparison but might not have the same level of certification and traceability as CRMs. When accuracy and traceability are critical, certified reference materials are preferred.