# NIMONIC Alloy 90 UNS N07090: Properties and Applications
## Introduction to NIMONIC Alloy 90
NIMONIC Alloy 90 (UNS N07090) is a nickel-chromium-cobalt-based superalloy known for its excellent high-temperature strength and corrosion resistance. Developed by Rolls-Royce in the 1940s, this alloy has become a staple material in aerospace and industrial applications where extreme conditions are encountered.
## Chemical Composition
The chemical composition of NIMONIC Alloy 90 plays a crucial role in its performance characteristics:
– Nickel (Ni): 55-60%
– Chromium (Cr): 18-21%
– Cobalt (Co): 15-21%
– Titanium (Ti): 2.0-2.8%
– Aluminum (Al): 1.0-1.8%
– Iron (Fe): ≤2.0%
– Manganese (Mn): ≤1.0%
– Silicon (Si): ≤1.0%
– Carbon (C): ≤0.13%
## Mechanical Properties
NIMONIC Alloy 90 exhibits impressive mechanical properties, especially at elevated temperatures:
Property | Value
Tensile Strength (Room Temp) | 950-1200 MPa
Yield Strength (Room Temp) | 550-850 MPa
Elongation | 20-30%
Hardness (Rockwell C) | 25-35
Creep Resistance | Excellent up to 815°C (1500°F)
## Physical Properties
The physical characteristics of NIMONIC Alloy 90 include:
– Density: 8.19 g/cm³
– Melting Range: 1290-1345°C (2354-2453°F)
– Thermal Expansion Coefficient: 13.5 μm/m·°C (20-100°C)
– Thermal Conductivity: 11.7 W/m·K (at 100°C)
– Electrical Resistivity: 1.25 μΩ·m
## Heat Treatment
Proper heat treatment is essential for optimizing the properties of NIMONIC Alloy 90:
Keyword: NIMONIC Alloy 90 UNS N07090
– Solution Treatment: 1080°C (1975°F) for 8 hours, air cool
– Aging Treatment: 700°C (1290°F) for 16 hours, air cool
This treatment sequence produces a fine gamma prime (γ’) precipitation that enhances the alloy’s strength at high temperatures.
## Corrosion Resistance
NIMONIC Alloy 90 demonstrates excellent resistance to:
– Oxidation up to 980°C (1800°F)
– Sulfidation
– Carburization
– Chloride stress corrosion cracking
– Hot gas corrosion
## Applications
Due to its exceptional properties, NIMONIC Alloy 90 finds use in various demanding applications:
### Aerospace Industry
– Turbine blades and discs
– Combustion chambers
– Afterburner components
– Exhaust systems
### Industrial Applications
– Gas turbine components
– Nuclear reactor parts
– High-temperature fasteners
– Heat treatment fixtures
– Chemical processing equipment
## Fabrication and Machining
Working with NIMONIC Alloy 90 requires special considerations:
– Forming: Best performed in annealed condition at elevated temperatures
– Welding: Can be welded using TIG or resistance welding methods
– Machining: Requires rigid setups, sharp tools, and slow speeds
– Grinding: Preferred finishing method for hardened material
## Advantages Over Other Alloys
NIMONIC Alloy 90 offers several advantages compared to similar high-temperature alloys:
– Better creep resistance than Inconel 718 at temperatures above 650°C (1200°F)
– Superior oxidation resistance compared to Waspaloy
– More stable microstructure than Udimet 500 at prolonged