# Alloy X-750 (UNS N07750) Properties and Applications
## Introduction to Alloy X-750
Alloy X-750, also known as UNS N07750, is a nickel-chromium alloy that is precipitation-hardenable. It is renowned for its excellent mechanical properties, high strength, and corrosion resistance at elevated temperatures. This alloy is widely used in various industries due to its ability to maintain structural integrity under extreme conditions.
## Chemical Composition
The chemical composition of Alloy X-750 plays a crucial role in its performance. Below is a breakdown of its primary elements:
– Nickel (Ni): 70% minimum
– Chromium (Cr): 14-17%
– Iron (Fe): 5-9%
– Titanium (Ti): 2.25-2.75%
– Aluminum (Al): 0.4-1.0%
– Niobium (Nb): 0.7-1.2%
– Carbon (C): 0.08% maximum
– Manganese (Mn): 1.0% maximum
– Silicon (Si): 0.5% maximum
– Sulfur (S): 0.01% maximum
– Copper (Cu): 0.5% maximum
## Mechanical Properties
Alloy X-750 exhibits outstanding mechanical properties, especially when heat-treated. Some key properties include:
– Tensile Strength: 1035 MPa (150 ksi) minimum
– Yield Strength: 690 MPa (100 ksi) minimum
– Elongation: 25% minimum
– Hardness: 35 HRC typical
– Fatigue Strength: Excellent resistance to cyclic loading
## Heat Treatment
The performance of Alloy X-750 can be enhanced through specific heat treatment processes. The standard heat treatment involves:
– Solution Annealing: 1150°C (2100°F) followed by rapid cooling
– Aging: 705°C (1300°F) for 20 hours, air cooling
– Double Aging: Optional for improved properties
## Corrosion Resistance
Alloy X-750 offers excellent resistance to various corrosive environments, including:
– Oxidation resistance up to 870°C (1600°F)
– Resistance to chloride-ion stress-corrosion cracking
– Good performance in acidic and alkaline environments
– Resistance to corrosion in high-temperature steam
## Applications of Alloy X-750
Due to its exceptional properties, Alloy X-750 finds applications in numerous industries:
### Aerospace Industry
Keyword: AlloyX-750 UNS N07750
– Jet engine components
– Turbine blades and discs
– Rocket engine parts
– Fasteners and springs
### Power Generation
– Gas turbine components
– Nuclear reactor parts
– Steam turbine blades
– Heat exchanger tubing
### Oil and Gas Industry
– Downhole tools
– Valve components
– High-pressure fittings
– Wellhead equipment
### Industrial Applications
– High-temperature springs
– Fasteners for extreme environments
– Chemical processing equipment
– Pressure vessels
## Fabrication and Machining
Alloy X-750 can be fabricated using standard techniques, though it requires specific considerations:
– Machining: Use sharp tools and slow speeds
– Welding: Recommended methods include TIG and resistance welding
– Forming: Can be cold or hot worked, but requires annealing
– Grinding: Use appropriate abrasives and cooling
## Advantages of Alloy X-750
The key advantages that make Alloy X-750 a preferred choice include:
– High strength-to-weight ratio
– Excellent creep resistance
– Good fatigue properties
– Maintains properties at high temperatures
– Long service life in harsh environments
## Conclusion
Alloy X-750 (UNS N07750) is a versatile nickel-based superalloy that offers an exceptional combination of strength, corrosion resistance, and high-temperature performance. Its wide range of applications across critical industries demonstrates its reliability and durability. Whether in aerospace