Jul 3 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Applications
Introduction
Incoloy alloy 908 is a nickel-iron alloy that has high tensile strength, fatigue crack growth resistance, good weldability, metallurgical stability and ductility, high fracture and impact toughness, low coefficient of thermal expansion, and resistance to oxygen embrittlement, which allows hot fabrication without cracking.
The following section will discuss in detail about Incoloy alloy 908.
Chemical Composition
The chemical composition Incoloy alloy 908 is outlined in the following table.
|
Element |
Content (%) |
|
Nickel, Ni |
47 - 51 |
|
Iron, Fe |
35.588 - 44.6 |
|
Chromium, Cr |
3.75 - 4.5 |
|
Niobium, Nb (Columbium, Cb) |
2.7 - 3.3 |
|
Titanium, Ti |
1.2 - 1.8 |
|
Manganese, Mn |
≤1 |
|
Aluminum, Al |
0.75 - 1.25 |
|
Cobalt, Co |
≤0.50 |
|
Copper, Cu |
≤0.50 |
|
Silicon, Si |
≤0.50 |
|
Carbon, C |
≤0.030 |
|
Phosphorous, P |
≤0.015 |
|
Boron, B |
≤0.012 |
|
Sulfur, S |
≤0.0050 |
Physical Properties
The following table shows the physical properties of Incoloy alloy 908.
|
Properties |
Metric |
Imperial |
|
Density |
8.17 g/cm3 |
0.295 lb/in3 |
|
Melting point |
1361-1410°C |
2482-2570°F |
Mechanical Properties
The mechanical properties of Incoloy alloy 908 are displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
1172 MPa |
170000 psi |
|
Yield strength |
827 MPa |
120000 psi |
|
Elongation at break |
12% |
12% |
Thermal Properties
The thermal properties of Incoloy alloy 908 are given in the following table
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@93°C/199°F) |
8.59 µm/m°C |
4.77 µin/in°F |
|
Thermal conductivity |
11.05 W/mK |
76.69 BTU.in/hrft².°F |
Other Designations
An equivalent material to Incoloy alloy 908 includes ASTM B 872.
Applications
The following are the list of applications of Incoloy alloy 908:
-
Prototype fusion reactors
-
High-strength cryogenic applications.