Alloy 825

Alloy 825  | UNS N08825 | 2.4858
Alloy 825 is a Nickel-iron-chromium alloy with additions of molybdenum, copper and titanium.
The alloys chemical composition provides exceptional resistance to many corrosive environments.
The Nickel content is sufficient for resistance to Chloride-ion stress corrosion cracking.
The nickel, combined with molybdenium and copper, also gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acid.
The molybdenium also aids resistance to pitting and crevice corrosion.
The alloys Chromium content confers resistance to a variety of oxidizing substances such as nitric acid, nitrates and oxidizing salts.
The titanium addition, with appropriate heat treatment, will stabilize the alloy against sensitization to intergranular corrosion.
Good resistance to stress corrosion cracking.
Satisfactory resistance to pitting and crevice corrosion.
Good resistance to oxidising and non-oxidising hot acids.
Good mechanical properties at both room and elevated temperatures up to approximately 550 deg.C (1020 deg. F).
Permission for pressure-vessel use at wall temperature up to 425 deg. C (800 deg. F).

Typical industrial sectors:

• Components such as heating coils, tanks, crates, baskets and chains in sulfuric acid pickling plants
• Fuel element dissolvers
• Sea water cooled heat exchangers
• Pipelines carrying wet sulphur dioxide gas and pulp digesters in the papermaking process
• Heat exchangers
• Evaporators
• Scrubbern
• Air cooled heat exchangers