Inconel 690

Inconel Alloy 690 (UNS designation N06690) is a high-chromium nickel alloy with excellent resistance to many corrosive aqueous media and high-temperature atmospheres. The alloy' s high chromium content gives it excellent resistance to aqueous corrosion by oxidizing acids (especially nitric acid) and salts, and to sulfidation at high-temperatures.

Applications involving nitric acid or nitric-plus-hydrochloric acid. Examples are tail-gas reheaters used in production of nitric acid and steam-heating coils in nitric- plus-hydrochloric acid solutions used for pickling stainless steels and reprocessing nuclear fuels.

Inconel 690 is also useful for high-temperature service in gases containing sulfur.

Inconel 690 has good resistance to oxidizing chemicals, such as nitric acid, and to sulfur-containing gases at high temperature. Inconel 690 has a superior stress cracking resistance than Inconel 600 in steam generation nuclear reactors for piping, separators and weldments.