Alloy 925 (UNS N09925) is a precipitation-hardened version of Alloy 825. Based upon the same Nickel-Iron-Chromium composition, Titanium and Aluminium are specifically added to give a strengthening of the alloy during ageing. Its physical properties are consistent with Alloy 825 (Incoloy 825, UNS N08825, 2.4858) and as a nickel-based alloy it is resistant to stress corrosion cracking.
Due to it’s very high strength levels it is being selectively used as an alternative to Alloy 718 (Inconel 718, UNS N07718, 2.4668), as it can provide a significant cost saving. Alloy 925 is particularly suited to down-hole applications in sour gas wells , but can also be used in less aggressive applications as it resists general, pitting, crevice and stress corrosion cracking in most aqueous environments where chloride or sulphide ions may be present.
Incoloy and Inconel are registered trademarks of Special Metals Inc.