# Alloy 230 UNS R06230: Properties and Applications

## Introduction to Alloy 230 UNS R06230

Alloy 230, also known as UNS R06230, is a nickel-chromium-tungsten-molybdenum alloy that offers exceptional high-temperature strength and oxidation resistance. This superalloy is widely used in industries where extreme heat and corrosive environments are common.

## Chemical Composition

The unique properties of Alloy 230 stem from its carefully balanced chemical composition:

– Nickel (Ni): 57% minimum
– Chromium (Cr): 20-24%
– Tungsten (W): 13-15%
– Molybdenum (Mo): 1-3%
– Iron (Fe): 3% maximum
– Cobalt (Co): 5% maximum
– Carbon (C): 0.05-0.15%
– Manganese (Mn): 0.3-1.0%
– Silicon (Si): 0.25-0.75%
– Aluminum (Al): 0.2-0.5%
– Lanthanum (La): 0.005-0.05%

## Key Properties of Alloy 230

### High-Temperature Strength

Alloy 230 maintains excellent mechanical properties at elevated temperatures, making it suitable for applications up to 2100°F (1150°C). Its high creep-rupture strength is particularly notable.

### Oxidation Resistance

The alloy forms a protective chromium oxide layer that provides outstanding resistance to oxidation in high-temperature environments.

### Thermal Stability

Alloy 230 demonstrates remarkable microstructural stability during long-term exposure to high temperatures.

### Corrosion Resistance

This alloy offers good resistance to various corrosive environments, including carburizing and nitriding atmospheres.

## Mechanical Properties

At room temperature, Alloy 230 typically exhibits:

– Tensile Strength: 120-150 ksi (827-1034 MPa)
– Yield Strength: 60-90 ksi (414-621 MPa)
– Elongation: 40-50%
– Hardness: 80-100 HRB

## Fabrication and Processing

Alloy 230 can be fabricated using standard techniques:

– Hot working: 2100-2250°F (1149-1232°C)
– Cold working: Possible but requires annealing
– Welding: Readily weldable using matching filler metal
– Machining: More difficult than austenitic stainless steels

## Heat Treatment

The standard heat treatment for Alloy 230 involves:

– Solution annealing at 2150°F (1177°C) followed by rapid cooling
– Stress relieving at 1600-1800°F (871-982°C) when needed

## Applications of Alloy 230

### Aerospace Industry

– Combustion chamber components
– Turbine blades and vanes
– Afterburner parts

### Power Generation

– Gas turbine components
– Heat exchangers
– Combustor liners

### Industrial Processing

– Furnace components
– Heat treating equipment
– Chemical processing equipment

### Other Applications

– Nuclear reactors
– Petrochemical processing
– Waste incineration systems

## Advantages Over Other Alloys

Alloy 230 offers several advantages compared to similar high-temperature alloys:

– Better oxidation resistance than Alloy 625
– Superior creep strength to Alloy X
– More cost-effective than cobalt-based alloys
– Better fabricability than some nickel-based superalloys

## Limitations and Considerations

While Alloy 230 is an excellent material for many applications, there are some limitations to consider:

– Not suitable for highly reducing environments
– Limited resistance to sulfur-bearing atmospheres
– Higher cost than standard stainless steels
– Requires specialized welding techniques

## Conclusion

Alloy 230 UNS R06230 is a versatile nickel-based superalloy that combines excellent high-temperature strength with outstanding