ATI 925 alloy (UNS N09925) is an age-hardenable nickel-iron-chromium alloy that combines good high strength properties and excellent corrosion resistance. The addition of molybdenum and copper gives the alloy resistance to reducing chemicals, and to pitting and crevice corrosion. The high chromium content provides resistance to oxidizing conditions, while the nickel protects the alloy from chloride ion stress corrosion cracking. The alloy is made age-hardenable by the addition of aluminum and titanium.

This alloy is often chosen for liquid and gaseous applications where a combination of high strength and corrosion resistance is required. ATI 925 alloy provides excellent resistance to corrosion cracking caused by hydrogen sulfide in sour gas applications. Applications include down-hole and above ground components.