# Alloy 90 UNS N07090: Properties and Applications
## Introduction to Alloy 90 UNS N07090
Alloy 90, also known as UNS N07090, is a nickel-chromium-cobalt alloy that offers excellent high-temperature strength and corrosion resistance. This superalloy is widely used in demanding applications where both mechanical properties and resistance to oxidation are critical.
## Chemical Composition
The chemical composition of Alloy 90 plays a significant role in its performance characteristics:
– Nickel (Ni): 55-60%
– Chromium (Cr): 18-21%
– Cobalt (Co): 15-21%
– Iron (Fe): ≤3.0%
– Molybdenum (Mo): ≤1.0%
– Titanium (Ti): 2.0-3.0%
– Aluminum (Al): 1.0-2.0%
– Carbon (C): ≤0.10%
– Manganese (Mn): ≤1.0%
– Silicon (Si): ≤1.0%
## Mechanical Properties
Alloy 90 exhibits impressive mechanical properties, especially at elevated temperatures:
– Tensile Strength: 1200-1400 MPa (at room temperature)
– Yield Strength: 800-1000 MPa (at room temperature)
– Elongation: 15-25%
– Hardness: 30-40 HRC
Keyword: Alloy 90 UNS N07090
– Creep Resistance: Excellent up to 980°C (1800°F)
## Physical Properties
The physical characteristics of Alloy 90 include:
– Density: 8.19 g/cm³
– Melting Range: 1290-1350°C (2350-2460°F)
– Thermal Expansion Coefficient: 13.5 μm/m·°C (20-1000°C)
– Thermal Conductivity: 11.2 W/m·K (at 100°C)
– Electrical Resistivity: 1.18 μΩ·m (at 20°C)
## Key Features and Advantages
Alloy 90 offers several notable benefits:
– Exceptional high-temperature strength
– Outstanding oxidation resistance up to 1100°C (2010°F)
– Good resistance to thermal fatigue
– Excellent creep-rupture properties
– Maintains mechanical properties at elevated temperatures
– Good fabricability and weldability
## Heat Treatment
Proper heat treatment is essential for optimizing Alloy 90’s properties:
– Solution Annealing: 1080-1120°C (1975-2050°F) followed by rapid cooling
– Aging Treatment: 700-800°C (1290-1470°F) for 16 hours
– Stress Relieving: 870-900°C (1600-1650°F) for 1-2 hours
## Applications of Alloy 90
Alloy 90 finds use in various demanding applications across multiple industries:
### Aerospace Industry
– Turbine blades and vanes
– Combustion chambers
– Afterburner components
– Exhaust systems
### Power Generation
– Gas turbine components
– Steam turbine blades
– High-temperature fasteners
– Heat exchangers
### Industrial Applications
– Furnace components
– Heat treatment fixtures
– Chemical processing equipment
– Nuclear reactor components
## Fabrication and Machining
Working with Alloy 90 requires special considerations:
– Machining should be performed using rigid setups and positive rake tools
– Welding can be done using TIG or MIG processes with matching filler metals
– Forming operations should be performed at elevated temperatures
– Post-weld heat treatment is recommended for critical applications
## Corrosion Resistance
Alloy 90 demonstrates excellent resistance to:
– Oxidation at high temperatures
– Sulfidation
– Carburization
– Nitridation
– Chloride-induced stress corrosion cracking
## Comparison with Other