Super Alloy Inconel 725™ (UNS N07725)

Topics Covered

Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties


Super alloys are metallic alloys used at high temperatures above 540ºC (1000ºF) where high surface stability and deformation resistance are mainly required. Three major classes of super alloys include iron-base, nickel-base and cobalt-base alloys. The iron-base super alloys are generally wrought alloys with stainless steel technology. Nickel-base and cobalt-base super alloys may be cast or wrought based on its composition or application. Super alloys are commonly forged, rolled to sheet or produced in various shapes. However, highly alloyed compositions are produced as castings.

The following datasheet will discuss in detail about Inconel 725™, which is age-hardenable and has high strength and corrosion resistance.

Chemical Composition

The following table shows the chemical composition of Inconel 725™.

Elements Content (%)
Nickel, Ni 55 - 59
Chromium, Cr 19 - 22.5
Iron, Fe 9
Molybdenum, Mo 7 - 9.50
Niobium, Nb (Columbium, Cb) 2.75 - 4
Titanium, Ti 1 - 1.70
Aluminum, Al  0.35
Manganese, Mn  0.35
Silicon, Si  0.20
Carbon, C  0.030
Phosphorous, P  0.015
Sulfur, S  0.010

Physical Properties

The physical properties of Inconel 725™ are given in the following table.

Properties Metric Imperial
Density 8.3 g/cm³ 0.3 lb/in³
Melting point 1271-343ºC 2320-2449ºF

Mechanical Properties

The mechanical properties of Inconel 725™ are displayed in the following table.

Properties Metric Imperial
Tensile strength 855 MPa 124000 psi
Yield strength (@0.2%) 427 MPa 62000 psi
Modulus of elasticity 204 GPa 29600 ksi
Poissons ratio 0.31 0.31
Elongation at break 57% 57%
Hardness, Rockwell C 5 5

Thermal Properties

The thermal properties of Inconel 725™ are displayed in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@21-100°C/69.8-212°F) 13 µm/m°C 7.22 µin/in°F

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