2.4642 / UNS N06690
A high-chromium nickel alloy which has excellent resistance to many corrosive aqueous media and high-temperature atmospheres. The high chromium content imparts excellent resistance to corrosion by oxidizing acids solutions (in particular nitric acid) and salts and also high temperature sulphidation resistance. Alloy 690 has low corrosion rates and excellent resistance to stress corrosion cracking in a range of high temperature high purity water and as such it is widely used for steam generator tubing, baffles and tubesheets and other component in nuclear power generation. In addition to its corrosion resistance, alloy 690 has high strength, good metallurgical stability and is readily fabricated.