ALLOY825 is a titanium-stabilized fully austenitic
Ni-Fe-Cr alloy with additions of Cu + Mo
•good resistance to stress-corrosion cracking
•satisfactory resistance to pitting and crevice corrosion
•good resistance to oxidizing and non-oxidizing hot acids
•good mechanical properties at both room and elevated temperatures, up to approximately 550 °C (1020 °F)
•approval for pressure vessels with wall temperatures up to 450 °C (842 °F)
Alloy 825 is a versatile general engineering alloy with resistance to corrosion in acids and alkalis under both oxidizing and reducing conditions.
High nickel content gives the alloy virtual immunity to stress corrosion cracking.
Alloy 825 is good in media as diverse as sulphuric, sulphurous, phosphoric, nitric and organic acids, alkalis such as sodium or potassium hydroxide, and acidic chloride solutions.
The versatility of Alloy 825 is illustrated by its use in nuclear fuel element dissolvers where a variety of corrosive media, e. g. sulphuric and nitric acids and sodium hydroxide, are handled in the same equipment.
Alloy 825 is used in a wide variety of applications up to a temperature of approximately 550 °C (1020 °F).
Typical applications are:
•components such as heating coils, tanks, crates, baskets and chains in sulphuric acid pickling plants
•fuel element dissolvers
•sea-water-cooled heat exchangers, offshore product piping systems; tubes and components in sour gas service
•heat exchangers, evaporators, scrubbers, dip pipes etc. in phosphoric acid production
•air-cooled heat exchangers in petroleum refineries
•combustion-resistant alloy for high pressure O2 applications