Nov 22 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesThermal PropertiesOther DesignationsFabrication and Heat Treatment Machinability Forming Welding Heat Treatment Forging Hot Working Cold Working Annealing HardeningApplications
Introduction
Super alloys have good creep and oxidation resistance, and can be formed in different shapes. They contain a number of elements in a variety of combinations to achieve the desired result, and can function at very high temperatures and mechanical stress. They are classified into three groups such as nickel-based, iron-based and cobalt-based alloys.
Nimonic 90™ is a nickel-chromium-cobalt alloy which can be strengthened by adding aluminum and titanium.
Chemical Composition
The following table shows the chemical composition of Nimonic 90™.
| Element |
Content (%) |
| Iron, Fe |
58.5 |
| Chromium, Cr |
19.5 |
| Cobalt, Co |
18 |
| Titanium, Ti |
2.5 |
| Aluminum, Al |
1.5 |
Physical Properties
The physical properties of Nimonic 90™ are outlined in the following table.
| Properties |
Metric |
Imperial |
| Density |
8.18 g/cm³ |
0.296 lb/in³ |
| Melting point |
1344°C |
2450°F |
Thermal Properties
The thermal properties of Nimonic 90™ are given in the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient (@ 20-100°C/68-212°F) |
12.7 µm/m°C |
7.1 µin/in°F |
| Thermal conductivity (@ 20°C/68°F) |
11.47 W/mK |
80.46 BTU in/hr.ft².°F |
Other Designations
Other designations that are equivalent to Nimonic 90™ include:
- AMS 5829
- DIN 2.4632
- DIN 2.4969
Fabrication and Heat Treatment
Machinability
Nimonic 90™ can be machined using conventional 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. Heavy lubricants are used for boring, drilling, broaching or tapping.
Forming
Nimonic 90™ can be formed using all conventional techniques
Welding
Nimonic 90™ is welded using shielded metal-arc welding, gas-tungsten arc welding, gas metal-arc welding, and submerged-arc welding methods.
Heat Treatment
Nimonic 90™ is heat treated by annealing at 1080°C (1975°F) for 8 h followed by cooling.
Forging
Nimonic 90™ is forged at 983 to 1177°C (1800 to 2150°F).
Hot Working
Nimonic 90™ is hot worked at temperatures ranging from 983 to 1177°C (1800 to 2150°F).
Cold Working
Nimonic 90™ can be cold worked using standard tooling.
Annealing
Nimonic 90™ is annealed at 1080°C (1975°F) for 8 h followed by cooling.
Hardening
Nimonic 90™ can be hardened by cold working.
Applications
Nimonic 90™ is used in high temperature and strength gas turbine components.