Nov 20 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Introduction
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 |