Nov 15 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Cold Working
Annealing
Applications
Introduction
Super alloys are also called high performance alloys. They have the capacity to function under very high temperatures and severe mechanical stress, and also where high surface stability is required. They have good creep and oxidation resistance. Super alloys contain many elements in a variety of combinations so as to achieve the desired result. Strengthening of super alloys is performed by solid-solution hardening, work hardening, and precipitation hardening methods.
There are three types of super alloys, namely cobalt-base, nickel-base, and iron-base. All of these can be used at temperatures above 540°C (1000°F).
Super alloy 29-17™ is an iron-based alloy. The chemical composition is closely controlled so as to provide the alloy with a low, uniform, thermal expansion feature.
The following datasheet will provide more details about super alloy 29-17™.
Chemical Composition
The following table shows the chemical composition of super alloy 29-17™.
|
Element |
Content (%) |
|
Iron, Fe |
53 |
|
Nickel, Ni |
29 |
|
Cobalt, Co |
17 |
|
Manganese, Mn |
0.50 max |
|
Silicon, Si |
0.20 max |
|
Chromium, Cr |
0.20 max |
|
Copper, Cu |
0.20 max |
|
Molybdenum, Mo |
0.20 max |
|
Aluminum, Al |
0.10 max |
|
Zirconium, Zr |
0.10 max |
|
Titanium, Ti |
0.10 max |
|
Magnesium, Mg |
0.10 max |
|
Carbon, C |
0.04 max |
Physical Properties
The physical properties of super alloy 29-17™ are outlined in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
8.35 g/cm³ |
0.302 lb/in³ |
|
Melting point |
1449°C |
2640°F |
Other Designations
Equivalent materials to super alloy 29-17™ are provided below:
-
AMS 7726
-
AMS 7727
-
AMS 7728
-
ASTM F15
-
MIL I-23011 Class 1
Fabrication and Heat Treatment
Machinability
Super alloy 29-17™ is machinable using conventional methods.
Forming
As Super alloy 29-17™ has good ductility, it can be easily formed using conventional methods.
Welding
Super alloy 29-17™ is easily weldable by the standard procedures.
Cold Working
Super alloy 29-17™ can be cold worked easily using the standard methods.
Annealing
Annealing of super alloy 29-17™ should be done only if necessary at 1093°C (2000°F) and then air cooled. If annealing is done after cold working, it will affect the thermal expansion characteristics. However, this can be repaired by performing annealing process in hydrogen atmosphere at 899°C (1650°F) for 1h. Then the temperature should be increased to 1099°C (2010°F) and held for 15 min, which is followed by cooling to room temperature within 1h.
Applications
Super alloy 29-17™ can be applied in glass sealing of metal components, or lead wires into hard glass/ceramic devices. It is also used in applications e.g. integrated circuits packaging, where low expansion with temperature change is essential.