Incoloy® alloy 800 - Heat Resisting Alloy (Ni32.5/Cr21/Fe) - Material Information

Incoloy® alloy 800 is a nickel–chromium–iron alloy designed for outstanding oxidation, carburization, and corrosion resistance under high-temperature conditions. With its stable austenitic microstructure, this material maintains strength and ductility even after long-term exposure to elevated temperatures, making it a preferred choice in the chemical, nuclear, and heat-treatment industries.

Material Overview

The alloy consists primarily of 32.5% nickel, 21% chromium, and a balanced iron content, resulting in an oxidation-resistant solid solution that withstands temperatures up to 1100 °C. Chromium ensures the formation of a protective Cr?O? layer, while nickel contributes to stability against chloride stress corrosion cracking. Incoloy 800 exhibits tensile strengths exceeding 550 MPa at room temperature and retains more than 60% of that value at 700 °C (Luo et al., 2022). Corrosion testing in high-temperature steam showed an increase in ultimate tensile strength by 12.5% after exposure at 575 °C and 23.5 MPa for 500 hours, attributed to microstructural refinement and secondary phase precipitation. However, ductility decreased due to oxide film formation along grain boundaries. Oxidation studies reveal that in N?/H?O/H?S atmospheres, sulfidation dominates, forming protective FeCr?S? layers that enhance long-term stability (Kim & Lee, 2017).

Applications and Advantages

Incoloy 800 and its variants (800H, 800HT) are widely used in heat exchangers, nuclear steam generator tubing, chemical processing plants, and high-temperature furnace systems. Their superior resistance to carburization and scaling ensures reliability in CO- and H?-rich environments. The alloy’s consistent performance under cyclic heating and mechanical stress has led to its adoption in supercritical water reactors (SCWR) and very high temperature reactor (VHTR) components. Its weldability and resistance to creep deformation further extend its use to structural components in aerospace and power generation sectors. Compared to stainless steels, Incoloy 800 offers greater thermal fatigue resistance and corrosion performance in aggressive mixed-gas environments.

Goodfellow Availability

Goodfellow supplies Incoloy® alloy 800 in standard and custom forms including tubes, wires, and foils for high-temperature and corrosive applications. All materials are produced to stringent specifications ensuring uniform mechanical and thermal performance. Explore nickel-based superalloys such as Incoloy 800 through the Goodfellow product finder.

References

• Luo, X., Li, W., & Cota-Sanchez, G. (2022). Mechanical property and microstructure characterization of Incoloy 800H alloy and its welds after corrosion testing in high temperature steam. Nuclear Engineering and Design, 388, 111970. https://doi.org/10.1016/j.nucengdes.2022.111970
• Kim, M. J., & Lee, D. B. (2017). High-temperature corrosion of Incoloy alloy 800 in N?/H?S gas. Applied Mechanics and Materials, 864, 3–9. https://doi.org/10.4028/www.scientific.net/AMM.864.3
• Li, H., Zheng, W., Du, B., Yin, H., He, X., Moa, T., & Yang, X. (2022). The high temperature corrosion of Incoloy 800H alloy at three different atmospheres. Journal of Nuclear Science and Technology, 59(7), 1025–1037. https://doi.org/10.1080/00223131.2022.2089756
• Rao, K. S. R. K., & Praveena, K. (2014). Manufacturing of Incoloy-800 tubes for nuclear steam generator systems. Conference Paper.
• Ganesan, P., Plyburn, J. A., & Tassen, C. S. (1995). INCOLOY alloy 803: a cost effective alloy for high temperature service. Inco Alloys International Technical Paper.