# Alloy 690 UNS N06690: Properties and Applications in High-Temperature Environments
Alloy 690 UNS N06690: Properties and Applications in High-Temperature Environments
Alloy 690 UNS N06690 is a nickel-chromium-iron alloy known for its exceptional resistance to high-temperature oxidation and corrosion. This material is widely used in industries where components are exposed to extreme conditions, such as nuclear power plants, chemical processing, and aerospace applications.
Chemical Composition
The chemical composition of Alloy 690 plays a crucial role in its performance characteristics:
- Nickel (Ni): 58-63%
- Chromium (Cr): 27-31%
- Iron (Fe): 7-11%
- Carbon (C): ≤0.05%
- Manganese (Mn): ≤0.50%
- Silicon (Si): ≤0.50%
- Copper (Cu): ≤0.50%
- Aluminum (Al): ≤0.50%
- Titanium (Ti): ≤0.50%
Key Properties
Keyword: Alloy 690 UNS N06690
High-Temperature Resistance
Alloy 690 maintains excellent mechanical properties at elevated temperatures, withstanding temperatures up to 1100°C (2012°F) in oxidizing environments.
Corrosion Resistance
The alloy demonstrates outstanding resistance to:
- Oxidation in high-temperature steam
- Stress corrosion cracking
- Intergranular attack
- Pitting and crevice corrosion
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 550-690 MPa |
| Yield Strength | 240-310 MPa |
| Elongation | 30-45% |
| Hardness (Rockwell B) | 85-95 |
Applications
Alloy 690 finds extensive use in demanding environments:
Nuclear Industry
The material is particularly valuable in nuclear power generation for:
- Steam generator tubes
- Reactor vessel internals
- Control rod drive mechanisms
Chemical Processing
Its corrosion resistance makes it ideal for:
- Heat exchangers
- Reaction vessels
- Piping systems
Aerospace Applications
The alloy is used in:
- Combustion chambers
- Afterburner components
- High-temperature fasteners
Fabrication and Welding
Alloy 690 can be fabricated using standard techniques,
