# Alloy 263 UNS N07263: Properties and Applications
## Introduction to Alloy 263
Alloy 263, also known as UNS N07263, is a nickel-chromium-cobalt-molybdenum alloy that offers exceptional high-temperature strength and oxidation resistance. This superalloy is widely used in demanding applications where extreme temperatures and corrosive environments are present.
## Chemical Composition
The chemical composition of Alloy 263 plays a crucial role in its performance characteristics:
– Nickel (Ni): 51% (base element)
– Chromium (Cr): 20%
– Cobalt (Co): 20%
– Molybdenum (Mo): 5.9%
– Titanium (Ti): 2.2%
– Aluminum (Al): 0.6%
– Carbon (C): 0.06% max
– Iron (Fe): 0.7% max
– Manganese (Mn): 0.6% max
– Silicon (Si): 0.4% max
## Mechanical Properties
Alloy 263 exhibits impressive mechanical properties across a wide temperature range:
### Room Temperature Properties
– Tensile Strength: 950-1200 MPa
– Yield Strength: 550-850 MPa
– Elongation: 30-50%
Keyword: Alloy 263 UNS N07263
– Hardness: 200-250 HB
### Elevated Temperature Properties
– Maintains strength up to 980°C (1800°F)
– Excellent creep resistance
– Good fatigue resistance
## Physical Properties
The physical characteristics of Alloy 263 include:
– Density: 8.36 g/cm³
– Melting Range: 1315-1370°C (2400-2500°F)
– Thermal Expansion Coefficient: 13.5 μm/m°C (20-1000°C)
– Thermal Conductivity: 11.2 W/m·K at 100°C
## Key Features and Advantages
Alloy 263 offers several notable benefits:
– Exceptional high-temperature strength
– Outstanding oxidation resistance up to 980°C
– Good resistance to thermal fatigue
– Excellent fabricability and weldability
– Resistance to carburization and nitridation
– Maintains mechanical properties after long-term exposure to high temperatures
## Heat Treatment
Proper heat treatment is essential for optimizing the properties of Alloy 263:
– Solution Annealing: Typically performed at 1150-1200°C (2100-2200°F) followed by rapid cooling
– Aging: Often carried out at 800°C (1470°F) for 8 hours to enhance creep resistance
## Applications of Alloy 263
Due to its unique combination of properties, Alloy 263 finds use in various demanding applications:
### Aerospace Industry
– Combustion chamber components
– Afterburner parts
– Turbine casings
– Exhaust systems
### Power Generation
– Gas turbine components
– Combustion liners
– Transition ducts
– Heat exchangers
### Industrial Applications
– High-temperature fasteners
– Furnace components
– Chemical processing equipment
– Nuclear reactor components
## Fabrication and Machining
Alloy 263 can be fabricated using standard techniques, though it requires special considerations:
### Forming
– Hot working preferred between 1050-1200°C
– Cold working possible but requires intermediate annealing
### Machining
– Requires rigid machine setups
– Use positive rake angles
– Maintain sharp cutting tools
– Use heavy-duty lubricants
### Welding
– Can be welded using TIG, MIG, and resistance welding methods
– Post-weld heat treatment recommended for critical applications
## Comparison with Similar Alloys
Alloy 263 offers advantages over other high-temperature alloys:
– Better creep resistance than Alloy 625 at temperatures above 700°C
– Superior oxidation resistance compared to Alloy 718
