Alloy 48 UNS K94800: Properties and Applications in Industry

# Alloy 48 UNS K94800: Properties and Applications in Industry

## Introduction to Alloy 48 UNS K94800

Alloy 48, also known by its UNS designation K94800, is a nickel-iron alloy with controlled thermal expansion characteristics. This specialized material finds extensive use in applications where precise dimensional stability across temperature variations is crucial.

## Chemical Composition

The chemical composition of Alloy 48 UNS K94800 typically includes:

– Nickel: 47-49%
– Iron: Balance
– Manganese: ≤0.30%
– Silicon: ≤0.20%
– Carbon: ≤0.05%
– Sulfur: ≤0.020%

This carefully balanced composition gives Alloy 48 its unique thermal expansion properties.

## Physical Properties

Alloy 48 exhibits several notable physical properties:

– Density: 8.25 g/cm³
– Melting Range: 1425-1475°C (2600-2690°F)
– Curie Temperature: Approximately 400°C (750°F)
– Electrical Resistivity: 49 μΩ·cm at 20°C
– Thermal Conductivity: 11.7 W/m·K at 20°C

## Mechanical Properties

The mechanical properties of Alloy 48 UNS K94800 include:

– Tensile Strength: 517 MPa (75 ksi) typical
– Yield Strength: 276 MPa (40 ksi) typical
– Elongation: 30% typical in 2 inches
– Hardness: Rockwell B 80 typical
– Modulus of Elasticity: 138 GPa (20 x 10⁶ psi)

## Thermal Expansion Characteristics

Alloy 48 is particularly valued for its thermal expansion properties:

– Coefficient of Thermal Expansion (20-400°C): ~9.5 x 10⁻⁶/°C
– Matches closely with many glasses and ceramics
– Maintains dimensional stability over wide temperature ranges

## Industrial Applications

### Electronics Industry

Alloy 48 finds extensive use in electronic applications:

– Lead frames for integrated circuits
– Glass-to-metal seals in electronic components
– Hermetic seals for sensitive electronic devices

### Aerospace Applications

The aerospace industry utilizes Alloy 48 for:

– Instrument components requiring thermal stability
– Sensor housings
– Precision measurement devices

### Energy Sector

In energy applications, Alloy 48 is used for:

– Seals in power generation equipment
– Components in nuclear reactors
– Thermocouple protection tubes

### Medical Devices

The medical industry benefits from Alloy 48 in:

– Implantable device components
– Diagnostic equipment
– Precision surgical instruments

## Fabrication and Processing

Alloy 48 can be processed using standard techniques:

– Machining: Can be machined using conventional methods but requires sharp tools
– Forming: Can be cold worked but may require annealing
– Welding: Can be welded using standard techniques
– Heat Treatment: Typically annealed at 870-980°C (1600-1800°F)

## Advantages Over Other Materials

Alloy 48 offers several advantages compared to other materials:

– Better thermal expansion match with glass than many other alloys
– Good corrosion resistance in many environments
– Excellent dimensional stability
– Maintains properties over wide temperature ranges

## Limitations and Considerations

While highly useful, Alloy 48 has some limitations:

– Not suitable for high-stress applications
– Limited availability in some forms
– Requires careful handling during fabrication
– May require special processing for optimal performance

## Future Trends

The demand for Alloy 48 UNS K94800 is expected to grow in:

– Advanced electronics packaging
– Miniaturized devices
– High-precision instrumentation
– Emerging energy technologies

## Conclusion

Alloy 48 UNS K94800 remains a critical material in industries requiring