Inconel 690 is a high-chromium nickel-based alloy developed to provide excellent resistance to corrosion and oxidation in demanding high-temperature environments. Its high nickel content contributes to resistance against stress-corrosion cracking, while approximately 30% chromium provides strong resistance to oxidizing media.

A major application of Inconel 690 is nuclear power equipment. The alloy is widely associated with steam-generator tubing and other components exposed to high-temperature water environments where long-term corrosion resistance and structural reliability are critical.

Inconel 690 also provides good resistance to many oxidizing chemicals and high-temperature gases. Its combination of corrosion resistance, oxidation resistance and mechanical stability makes it suitable for heat exchangers, chemical-processing equipment and thermal-processing components.

Unlike Inconel 718, Inconel 690 is not primarily selected for precipitation-hardened ultra-high strength. Its main advantage is environmental resistance, particularly in severe oxidizing and high-temperature aqueous conditions.