# Alloy 25 (UNS R30605) Properties and Applications
## Introduction to Alloy 25 (UNS R30605)
Alloy 25, also known by its UNS designation R30605, is a high-performance nickel-chromium alloy with excellent oxidation resistance and high-temperature strength. This alloy is particularly valued for its ability to maintain structural integrity in extreme environments, making it a popular choice in aerospace, chemical processing, and power generation industries.
## Chemical Composition
The chemical composition of Alloy 25 plays a crucial role in its performance characteristics:
– Nickel (Ni): 58-63%
– Chromium (Cr): 20-23%
– Iron (Fe): ≤5%
– Manganese (Mn): ≤1%
– Silicon (Si): ≤1%
– Carbon (C): ≤0.1%
– Aluminum (Al): ≤0.5%
– Titanium (Ti): ≤0.5%
## Physical Properties
Alloy 25 exhibits several notable physical properties:
– Density: 8.19 g/cm³
– Melting Range: 1350-1400°C (2460-2550°F)
– Thermal Conductivity: 11.4 W/m·K at 100°C
– Electrical Resistivity: 1.18 μΩ·m at 20°C
– Coefficient of Thermal Expansion: 14.4 μm/m·K (20-1000°C)
## Mechanical Properties
The mechanical properties of Alloy 25 make it suitable for demanding applications:
– Tensile Strength: 655 MPa (95 ksi) at room temperature
– Yield Strength: 240 MPa (35 ksi) at room temperature
– Elongation: 40% in 50 mm
– Hardness: 80 HRB (Rockwell B scale)
## High-Temperature Performance
One of the most significant advantages of Alloy 25 is its exceptional performance at elevated temperatures:
– Maintains strength up to 980°C (1800°F)
– Excellent resistance to oxidation and carburization
– Good creep and rupture strength
– Resistant to thermal fatigue
## Corrosion Resistance
Alloy 25 offers outstanding corrosion resistance in various environments:
– Excellent resistance to oxidizing and reducing atmospheres
– Good performance in sulfur-containing environments
– Resistant to chloride-ion stress-corrosion cracking
– Maintains integrity in carburizing and nitriding atmospheres
## Fabrication and Welding
Alloy 25 can be fabricated using standard techniques with some considerations:
– Hot working should be performed between 870-1200°C (1600-2200°F)
– Cold working requires intermediate annealing
– Excellent weldability using conventional methods
– Post-weld heat treatment may be required for optimal properties
## Heat Treatment
Proper heat treatment enhances Alloy 25’s properties:
– Solution annealing: 1095-1205°C (2000-2200°F) followed by rapid cooling
– Stress relieving: 870-980°C (1600-1800°F)
– Aging treatments can be applied for specific applications
## Applications of Alloy 25
Alloy 25 finds use in numerous demanding applications:
### Aerospace Industry
– Turbine blades and vanes
– Combustion chambers
– Afterburner components
– Exhaust systems
### Chemical Processing
– Furnace components
Keyword: Alloy 25 UNS R30605
– Heat exchangers
– Retorts and muffles
– Catalyst support grids
### Power Generation
– Gas turbine components
– Heat recovery systems
– Boiler parts
– Nuclear reactor components
### Other Applications
– Industrial heating elements
– Petrochemical processing equipment
– Glass manufacturing components
– Waste incineration systems
## Advantages Over Other Alloys
Alloy 25 offers several advantages compared to similar high-temperature alloys:
– Better oxidation resistance than many nickel-based alloys
