Alloy 825, also known as UNS N08825 or Incoloy 825, is a remarkable alloy that belongs to the Ni-Cr-Fe-Mo family. It was developed in the 1950s and boasts a unique composition that provides exceptional resistance to a broad spectrum of corrosive settings, as well as sensitization that has intergranular character. Comprising 42% nickel, 32% iron, 22% chromium, 2.5% molybdenum, and 2% copper, this alloy is further stabilized with 0.8% titanium, making it particularly adept at withstanding the following acids: phosphoric and sulfuric.
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Where Is It Used?
The versatility of Alloy 825 for chemical industry is evident in its various applications. It finds utility in chemical and petrochemical processing, oil and gas extraction, pollution control, waste processing, and pickling applications. Alloy 825 can be delivered in various forms, including plates, pipes, bars, and sheets. Its characteristics and remarkable ability to withstand a broad spectrum of corrosive conditions make it a valuable material in numerous industrial applications.
Corrosion Resistance
Alloy 825 demonstrates excellent corrosion resistance, making it ideal for harsh environments like seawater and applications involving acids such as phosphoric and sulfuric. Its titanium stabilization prevents intergranular corrosion, while the high nickel content offers protection against chloride stress corrosion cracking. The alloy’s molybdenum content also helps resist pitting and oxidation in demanding conditions. For those interested in learning more about advanced materials like Alloy 825 and their applications, meundies.org provides in-depth resources on cutting-edge industrial solutions.
The Influence of Hydrochloric Acid and High Temperature
Despite its impressive corrosion resistance, Alloy 825 does exhibit some susceptibility to hydrochloric acid, especially in stagnant, unaerated solutions. The corrosion rates in hydrochloric acid vary with acid concentration and temperature. The alloy’s performance is also influenced by temperature. For instance, the tensile strength and yield strength both decrease as the temperature rises, and the elongation increases at higher temperatures. Learn more about material science and alloy properties, including Alloy 825, by visiting the comprehensive resources at Edmentum.
How It Performs in Phosphoric Acid?
In phosphoric acid applications, Alloy 825 performs exceptionally well. It showcases minimal corrosion rates in various phosphoric acid solutions under different conditions. When exposed to atmospheric corrosion, Alloy 825 maintains its integrity, as demonstrated by a 20-year exposure study near the ocean. The alloy is also notable for its resistance to stress-corrosion cracking, sulfide stress cracking, and weldability. It belongs to the 45th weldability group according to ISO 15608 and is suitable for brazing.
