Inconel 625 is a highly versatile nickel-chromium molybdenum alloy with outstanding resistance to corrosion in a wide range of aggressive environments. This solid solution strengthened alloy has a nominal chemical composition of nickel 58% min followed by chromium and molybdenum, with traces of iron, niobium and tantalum.
Known also by the trade names Haynes 625, Nickelvac 625, Alloy 625 and Nicrofer 6020, this high-performance material is weldable in all conditions and offers good resistance to creep at elevated temperatures. It has excellent resistance to oxidation and corrosion in the presence of reducing acids, alkalis, chlorides and salts. Its tensile and yield strength properties are enhanced by heat treatment, but it is not required for a precipitation hardening process.
The balanced composition of alloying elements grants inconel 625 good resistance to corrosion, particularly pitting and crevice corrosion, in chloride contaminated media at high temperatures. Chloride stress corrosion cracking is also effectively resistted due to the molybdenum content which acts in combination with niobium to distort the atomic matrix, making it difficult for the corrosive environment to penetrate the surface of the alloy.
This excellent combination of characteristics has made inconel 625 a popular choice for a range of applications. It is used in sour gas pipelines, hot sections of gas turbine engine ducting and combustion liners and spray bars, special seawater applications and high-temperature chemical processing environments. It is also often found in nuclear power applications such as reactor core and steam generator components and waste reprocessing equipment.
