# Alloy 907 UNS N19907: Properties and Applications
## Introduction to Alloy 907
Alloy 907, also known as UNS N19907, is a nickel-iron-based superalloy designed for high-temperature applications. This alloy is known for its excellent mechanical properties, corrosion resistance, and ability to withstand extreme environments. It is commonly used in aerospace, power generation, and chemical processing industries.
## Chemical Composition
The chemical composition of Alloy 907 plays a crucial role in its performance. Below is a typical composition:
– Nickel (Ni): 38-42%
– Iron (Fe): Balance
– Cobalt (Co): 12-16%
– Chromium (Cr): 0.5-1.5%
– Molybdenum (Mo): 2.5-3.5%
– Titanium (Ti): 1.3-1.8%
– Aluminum (Al): 0.2-0.6%
– Carbon (C): ≤0.06%
– Manganese (Mn): ≤0.50%
– Silicon (Si): ≤0.50%
– Sulfur (S): ≤0.015%
– Phosphorus (P): ≤0.015%
## Mechanical Properties
Alloy 907 exhibits outstanding mechanical properties, especially at elevated temperatures. Some key properties include:
– Tensile Strength: 1200-1400 MPa (at room temperature)
– Yield Strength: 800-1000 MPa (at room temperature)
– Elongation: 10-20% (at room temperature)
– Hardness: 30-40 HRC
– Creep Resistance: Excellent at temperatures up to 700°C (1292°F)
## Thermal Properties
The thermal properties of Alloy 907 make it suitable for high-temperature applications:
– Melting Range: 1350-1400°C (2462-2552°F)
– Thermal Conductivity: 11.5 W/m·K (at 20°C)
– Coefficient of Thermal Expansion: 12.5 × 10-6/°C (20-100°C)
## Corrosion Resistance
Alloy 907 offers excellent resistance to various corrosive environments, including:
– Oxidation resistance up to 1000°C (1832°F)
– Resistance to sulfur-containing environments
– Good performance in carburizing and nitriding atmospheres
– Resistance to chloride-induced stress corrosion cracking
## Applications of Alloy 907
Due to its unique combination of properties, Alloy 907 finds applications in several demanding industries:
### Aerospace Industry
– Turbine engine components
– Combustion chambers
– Afterburner parts
– Exhaust systems
### Power Generation
– Gas turbine components
– Heat exchangers
– Steam turbine blades
– Nuclear reactor components
### Chemical Processing
– Reactor vessels
– Heat exchangers
– Piping systems
– Valves and pumps
## Fabrication and Welding
Alloy 907 can be fabricated using standard methods, but requires special considerations:
– Hot working should be performed at 1050-1200°C (1922-2192°F)
– Cold working is possible but may require intermediate annealing
– Welding can be performed using gas tungsten arc welding (GTAW) or electron beam welding (EBW)
Keyword: Alloy 907 UNS N19907
– Post-weld heat treatment is often recommended
## Heat Treatment
Proper heat treatment is essential for optimizing the properties of Alloy 907:
– Solution annealing: 1050-1150°C (1922-2102°F) followed by rapid cooling
– Aging treatment: 700-800°C (1292-1472°F) for 16-24 hours
– Stress relieving: 850-900°C (1562-1652°F) for 2-4 hours
## Conclusion
