Overview and Applications of Incoloy 800

Incoloy 800 is a high-temperature alloy primarily composed of Ni and Cr, belonging to the Ni-Fe-Cr series of nickel-iron-based corrosion-resistant alloys. After rapid cooling from high temperatures, Incoloy 800 remains in the austenitic single-phase region, resulting in a single austenitic microstructure in its service state. This alloy features high chromium content and sufficient nickel content, providing excellent resistance to high-temperature corrosion, stress corrosion, and oxidation. It is commonly used in applications above 700°C, such as nuclear power evaporation heat transfer tubes and ultra-supercritical power generation units, as well as high-temperature equipment in the petrochemical industry (e.g., catalytic tubes, convection tubes, cracking tubes, reformer furnaces, and pigtail tubes). In environments like chlorides, low-concentration NaOH aqueous solutions, and high-temperature high-pressure water, it exhibits superior resistance to stress corrosion cracking, making it suitable for manufacturing equipment resistant to stress corrosion cracking. Under softening annealing conditions up to 600°C, Incoloy 800 can be applied in chemical industrial nuclear generators, nitric acid coolers, acetic anhydride cracking tube heat exchange equipment, and heat exchange tubes.

Characteristics of Incoloy 800

It offers good corrosion and heat resistance, outperforming general austenitic stainless steels and even Incoloy 600 alloy. In the fabrication of equipment resistant to corrosive stress cracking, it surpasses both Incoloy 600 and Monel 400 alloys. It maintains excellent mechanical properties at both low and high temperatures up to 800°C, along with good oxidation, reduction, and nitriding resistance, as well as favorable machinability. It is also suitable for wet corrosive environments. However, for applications above 600°C, the solution-annealed type Incoloy 800H is recommended. Incoloy 800 resists a variety of corrosive media. Its higher nickel content provides good resistance to stress corrosion cracking in wet environments. Increased chromium content enhances resistance to pitting and crevice corrosion. The alloy shows good resistance to nitric and organic acids but has limited resistance to sulfuric and hydrochloric acids, with potential pitting in halogen acids. This material exhibits strong corrosion resistance and also resists fresh water, steam, and mixtures of steam, air, and water, with excellent oxidation and carburization resistance. It is also resistant to hydrogen, nitrogen, and corrosion.

Chemical Composition of Incoloy 800:

Physical Properties of Incoloy 800:

Mechanical Properties of Incoloy 800 at Room Temperature:

Available in various specifications including plates, bars, strips, wires, discs, ring blanks, and ring forgings. Bars are supplied in forged-rolled condition, surface ground or turned; discs and ring blanks are supplied in forged state; rings are supplied in solution-treated condition; plates are supplied after solution treatment, alkali pickling, straightening, and edge trimming; strips are delivered cold-rolled, solution-treated, and descaled; wires are supplied in solution-pickled coil or straight form, or solution-treated straight fine-ground condition.