Description
Alloy Geek 904 High-Alloy Austenitic Stainless Steel Standard
Alloy 904, also known as UNS N08904 or 904L, is a high-alloy austenitic stainless steel with excellent corrosion resistance, particularly in aggressive environments. It contains elevated levels of chromium, nickel, and molybdenum, which contribute to its superior resistance to pitting and crevice corrosion. Alloy 904L is often used in applications where corrosion resistance is paramount, such as in chemical processing, petrochemical, pharmaceutical, and seawater handling industries.
The composition of Alloy 904 typically includes:
- Chromium (about 19-23%)
- Nickel (about 23-28%)
- Molybdenum (about 4-5%)
- Copper (about 1-2%)
- Small amounts of other elements like manganese, silicon, carbon, and sulfur
Key features and characteristics of Alloy 904:
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Corrosion Resistance: Alloy 904 is highly resistant to corrosion, especially in aggressive environments such as sulfuric acid, hydrochloric acid, and seawater. This makes it suitable for various applications in harsh chemical and marine environments.
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Pitting and Crevice Corrosion Resistance: The elevated levels of chromium, nickel, and molybdenum contribute to the alloy's excellent resistance to localized corrosion, including pitting and crevice corrosion.
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Applications: Alloy 904L is commonly used in industries involving chemical processing, pharmaceuticals, petrochemicals, food processing, and seawater handling. It's chosen for applications like heat exchangers, storage tanks, pipelines, and components exposed to corrosive media.
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Formability and Weldability: Alloy 904L can be easily formed and welded using common methods, making it versatile for various manufacturing processes.
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Heat Treatment: Alloy 904L is generally solution annealed to achieve its optimal properties.
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Forms: Alloy 904L is available in various forms, including sheets, plates, bars, tubes, and pipes.
Due to its exceptional corrosion resistance, Alloy 904L is highly valued in industries where aggressive chemical environments are present. If you're considering using Alloy 904L for a specific project, consulting with materials experts or manufacturers is recommended to ensure it meets your desired performance requirements, especially in terms of corrosion resistance and compatibility with the specific conditions of your application.
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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 do not have the same level of certification and traceability as CRMs. When accuracy and traceability are critical, certified reference materials are preferred.