Inconel 825 is an alloy made with nickel, chromium, and iron with contents of molybdenum, copper, and titanium which gives excellent resistance from numerous corrosive conditions. Nickel alloy 825 is a face-centered cubic cell with a matric phase. It is easy to measure its strength as for other possible crystal formations.
|INCONEL 825||NO8825||2.4858||NC 21 FeDU||B 704, B 705, B 423, B 163|
This nickel alloy 825’s chemical composition is crafted to provide exceptional resistance to various corrosive environments. Titanium oxide is formed in Inconel 825 & provides resistance to local attacks like pitting & crevice corrosion.
Chemical Properties of Inconel 825
Inconel 825 (UNS N08825/ W.Nr. 2.4858) is excellently resistant to both reducing and oxidizing acids. It also provides resistance to stress-corrosion cracking and to localized attack like pitting and crevice corrosion.
Inconel 825 has greater resistance from corrosion from sulfuric and phosphoric acids and seawater. Nickel alloy 825 is like the alloy 800 however with improved resistance from corrosion due to water. With augmentations of molybdenum, copper, and titanium this nickel-based steel alloy’s chemical combination has given outstanding resistance from numerous corrosive conditions.
Physical Properties of SS 825
Melting Point °C
Elastic Modulus (GPa)
Coeff of Thermal Expansion (μm/m/°C)
Thermal Conductivity (W/m.K)
Electrical Resistivity (μΩ.m)
When we consider Inconel 825 Vs. Incoloy 825, Incoloy 825 alloy products are heat-treated during the manufacturing process to develop a proper composition of stabilization, corrosion resistance, mechanical properties, and formation. To maintain these properties during fabrication, subsequent annealing must be done in between 1700 to 1800°F (930 to 980°C) followed by rapid air cooling or water quenching.
The hot-working temperature range for Incoloy alloy 825 is 1600°F to 2150°F (870°C to 1180°C). For ideal corrosion resistance, last hot working ought to be done at temperatures somewhere in the range of 1600°F and 1800°F (870°C and 980°C). Cooling after hot working ought to be air cool or quicker.
Content of titanium in nickel alloy 825 remunerated against sharpening in the as-welded condition. It builds its resistivity to intergranular corrosion after temperatures are in a reach that would make stable solidified stainless steels.
The alloy 825 has less working hardness due to the copper content. It can hence be used at cryogenic temperatures to high temperatures without any loss of mechanical properties. The composite 825 is popularly used around 540°C, with no adjustment in its microstructure and flexibility.
Inconel 825 is moderately simple to machine. All the standard techniques can be promptly utilized. It has ideal machining attributes in the tempered condition. The nickel alloy 825 is determined as ‘C’ alloys and tooling particulars are moderately utilized. Positive feeds, inflexible tooling, proper velocities, satisfactory oiling, or lubrication will give ideal outcomes.
Inconel Alloy 825 is readily weldable by the normal processes such as (GMAW (MIG), GTAW (TIG), SMAW (manual), SAW) during welding the joint must be clean to avoid contamination of the weld pool.
Nickel alloy 825 can be suitably welded by the protected metal circular segment.
The method of using alloy welding anode 135, the gas protects bend procedures utilizing combination filler metal 65, and the obstruction welding forms.
Specific Applications of Inconel 825
- Condensers in heat exchangers
- Oil and gas well equipment on the seashore
- Hydraulic systems
- Chemical injection lines
- Chemical process equipment and vessels
- Downhole control lines
- Control and instrumentation
- Acid Production
- Nuclear fuel processing
General applications of Incoloy 825
- Sulphuric acid piping and vessels
- Phosphoric acid evaporators
- Pickling tank heaters, pickling tanks, and equipment
- Chemical process equipment
- Propeller shafts
- Tank trucks
- Electrostatic precipitator electrodes
- Hot vessels for food, water, and seawater,
- Ammonium sulfate vessels
- Expansion bellows
- Marine exhaust systems
- Power station ash hoppers
NOTE: Inconel 825 is a registered trademark of Special Metals Corporation.