# Alloy738 UNS N06738: Properties and Applications
## Introduction to Alloy738 UNS N06738
Alloy738 UNS N06738 is a nickel-based superalloy known for its exceptional high-temperature strength and corrosion resistance. This material is widely used in demanding industrial applications where performance under extreme conditions is critical.
## Chemical Composition
The chemical composition of Alloy738 UNS N06738 includes:
– Nickel (Ni): 58-63%
– Chromium (Cr): 15-17%
– Cobalt (Co): 8-10%
– Molybdenum (Mo): 1.5-2.5%
– Aluminum (Al): 3.2-3.7%
– Titanium (Ti): 3.2-3.7%
– Iron (Fe): ≤1.0%
– Carbon (C): ≤0.10%
## Mechanical Properties
Alloy738 UNS N06738 exhibits impressive mechanical properties:
Keyword: Alloy738 UNS N06738
– Tensile Strength: 1200-1400 MPa
– Yield Strength: 800-1000 MPa
– Elongation: 10-20%
– Hardness: 35-45 HRC
– Creep Resistance: Excellent at temperatures up to 850°C (1562°F)
## Physical Properties
Key physical properties include:
– Density: 8.19 g/cm³
– Melting Range: 1315-1370°C (2400-2500°F)
– Thermal Conductivity: 11.4 W/m·K at 20°C
– Electrical Resistivity: 1.28 μΩ·m at 20°C
– Coefficient of Thermal Expansion: 13.5 μm/m·K (20-100°C)
## Heat Treatment
Alloy738 UNS N06738 typically undergoes the following heat treatment:
– Solution Annealing: 1120-1160°C (2050-2120°F) followed by rapid cooling
– Aging: 845-870°C (1550-1600°F) for 24 hours, air cool
– Stabilization: 760°C (1400°F) for 16 hours, air cool
## Corrosion Resistance
The alloy demonstrates excellent resistance to:
– Oxidation at high temperatures
– Sulfidation
– Carburization
– Chloride-induced stress corrosion cracking
– Hot corrosion in sulfur-containing environments
## Applications of Alloy738 UNS N06738
Due to its unique combination of properties, Alloy738 finds applications in:
### Aerospace Industry
– Turbine blades and vanes
– Combustion chambers
– Afterburner components
### Power Generation
– Gas turbine components
– Steam turbine blades
– Heat exchangers in nuclear plants
### Industrial Processing
– Chemical processing equipment
– Furnace components
– Heat treatment fixtures
### Oil and Gas
– Downhole tools
– Wellhead components
– Valve parts in corrosive environments
## Fabrication and Machining
Working with Alloy738 UNS N06738 requires special considerations:
– Machining: Requires rigid setups, sharp tools, and slow speeds
– Welding: Gas tungsten arc welding (GTAW) is preferred
– Forming: Hot working is recommended above 1000°C (1832°F)
– Grinding: Use aluminum oxide or silicon carbide wheels
## Comparison with Other Superalloys
Compared to similar alloys, Alloy738 offers:
– Better creep resistance than Inconel 718
– Higher temperature capability than Waspaloy
– Superior oxidation resistance than Alloy X
– Better phase stability than Rene 41
## Conclusion
Alloy738 UNS N06738 represents an excellent choice for applications requiring high strength and corrosion resistance at elevated temperatures. Its balanced combination of mechanical properties, fabricability, and environmental resistance makes