Super Alloy Incoloy(r) Alloy 825 (UNS N08825)

Super alloys have the ability to function at very high temperatures and mechanical stress, and also where high surface stability is required. They have good creep and oxidation resistance, and can be produced in a variety of shapes. They can be strengthened by solid-solution hardening, work hardening, and precipitation hardening.

Super alloys consist of a number of elements in a variety of combinations to achieve the desired result. They are further classified into three groups such as cobalt-based, nickel-based, and iron-based alloys.

Incoloy(r) alloy 825 is an austenitic nickel-iron-chromium alloy which is added with other alloying elements in order to improve its chemical corrosion resistant property. The following datasheet will provide more details about Incoloy(r) alloy 825.

Chemical Composition

The following table shows the chemical composition of Incoloy(r) alloy 825.

Element Content (%)
Nickel, Ni 38-46
Iron, Fe 22
Chromium, Cr 19.5-23.5
Molybdenum, Mo 2.50-3.50
Copper, Cu 1.50-3.0
Manganese, Mn 1
Titanium, Ti 0.60-1.20
Silicon, Si 0.50
Aluminum, Al 0.20
Carbon, C 0.050
Sulfur, S 0.030

Physical Properties

The physical properties of Incoloy(r) alloy 825 are given in the following table.

Properties Metric Imperial
Density 8.14 g/cm³ 0.294 lb/in³
Melting point 1385°C 2525°F

Mechanical Properties

The mechanical properties of Incoloy(r) alloy 825 are highlighted in the following table.

Properties Metric Imperial
Tensile strength (annealed) 690 MPa 100000 psi
Yield strength (annealed) 310 MPa 45000 psi
Elongation at break (annealed prior to test) 45% 45%

Thermal Properties

The thermal properties of Incoloy(r) alloy 825 are outlined in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (at 20-100°C/68-212°F) 14 µm/m°C 7.78 µin/in°F
Thermal conductivity 11.1 W/mK 77 BTU in/hr.ft².°F

Other Designations

Other designations that are equivalent to Incoloy(r) alloy 825 include:

  • ASTM B163
  • ASTM B423
  • ASTM B424
  • ASTM B425
  • ASTM B564
  • ASTM B704
  • ASTM B705
  • DIN 2.4858

Fabrication and Heat Treatment


Incoloy(r) alloy 825 can be machined using conventional machining methods which are used for iron-based alloys. Machining operations are performed using commercial coolants. High-speed operations such as grinding, milling or turning, are performed using water-based coolants.


Incoloy(r) alloy 825 can be formed using all conventional techniques.


Incoloy(r) alloy 825 is welded using gas-tungsten arc welding, shielded metal-arc welding, gas metal-arc welding, and submerged-arc welding methods.

Heat Treatment

Incoloy(r) alloy 825 is heat treated by annealing at 955°C (1750°F) followed by cooling.


Incoloy(r) alloy 825 is forged at 983 to 1094°C (1800 to 2000°F).

Hot Working

Incoloy(r) alloy 825 is hot worked below 927°C (1700°F).

Cold Working

Standard tooling is used for cold working Incoloy(r) alloy 825.


Incoloy(r) alloy 825 is annealed at 955°C (1750°F) followed by cooling.


Incoloy(r) alloy 825 is hardened by cold working.


Incoloy(r) alloy 825 is used in the following applications:

  • Acid production piping
  • Vessels
  • Pickling
  • Chemical process equipment.

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