# Alloy 230 UNS R06230: Properties and Applications

## Introduction to Alloy 230 UNS R06230

Alloy 230, also known by its UNS designation R06230, is a nickel-chromium-tungsten-molybdenum alloy that offers exceptional high-temperature strength and oxidation resistance. This advanced material is widely used in industries where extreme conditions are common, such as aerospace, power generation, and chemical processing.

## Chemical Composition

The chemical composition of Alloy 230 plays a crucial role in its performance characteristics:

– Nickel (Ni): 57% (minimum)
– Chromium (Cr): 20-24%
– Tungsten (W): 13-15%
– Molybdenum (Mo): 1-3%
– Iron (Fe): ≤3%
– Manganese (Mn): ≤0.5%
– Silicon (Si): ≤0.4%
– Aluminum (Al): 0.2-0.5%
– Carbon (C): 0.05-0.15%
– Lanthanum (La): 0.005-0.05%

## Mechanical Properties

Alloy 230 exhibits impressive mechanical properties across a wide temperature range:

– Tensile Strength: 120-150 ksi (827-1034 MPa)
– Yield Strength: 60-90 ksi (414-621 MPa)
– Elongation: 40-50%
– Hardness: 80-100 HRB
– Creep Strength: Excellent at temperatures up to 1800°F (982°C)

## Physical Properties

The physical characteristics of Alloy 230 include:

– Density: 0.305 lb/in³ (8.44 g/cm³)
– Melting Range: 2410-2490°F (1320-1365°C)
– Thermal Conductivity: 6.5 BTU·in/(hr·ft²·°F) at 70°F
– Electrical Resistivity: 45.5 μΩ·in at 70°F
– Coefficient of Thermal Expansion: 7.2 µin/(in·°F) between 70-1000°F

## Key Features and Advantages

Alloy 230 offers several distinct advantages that make it suitable for demanding applications:

– Exceptional high-temperature strength and stability
– Outstanding oxidation resistance up to 2100°F (1149°C)
– Good resistance to carburization and nitriding environments
– Excellent thermal fatigue resistance
– Good fabricability and weldability
– Long-term microstructural stability

## Common Applications

Due to its unique combination of properties, Alloy 230 finds use in numerous critical applications:

### Aerospace Industry

– Combustion chamber components
– Afterburner parts
– Turbine seals and rings

### Power Generation

– Gas turbine components
– Combustion liners
– Transition ducts
– Heat exchangers

### Industrial Processing

– Furnace components
– Heat treatment fixtures
– Chemical processing equipment
– Petrochemical reactors

## Fabrication and Welding

Alloy 230 can be successfully fabricated using standard techniques:

– Hot working should be performed between 2100-2250°F (1149-1232°C)
– Cold working requires intermediate annealing
– Welding can be done using GTAW, GMAW, and SMAW processes
– Post-weld heat treatment is generally not required

## Comparison with Similar Alloys

When compared to other nickel-based superalloys:

– Better oxidation resistance than Alloy 625 and Alloy X
– Superior creep strength to Alloy 617 at high temperatures
– More stable microstructure than Alloy 263
– Better fabricability than some cobalt-based alloys

## Conclusion

Alloy 230 UNS R06230 represents an excellent choice for applications requiring long-term performance in extreme environments. Its combination of high-temperature strength,