# Nickel Alloy UNS N07090: Properties and Applications

## Introduction to UNS N07090

Nickel Alloy UNS N07090, also known as Waspaloy, is a high-strength, corrosion-resistant superalloy primarily composed of nickel, chromium, and cobalt. This precipitation-hardenable alloy is renowned for its exceptional mechanical properties at elevated temperatures, making it a preferred material for demanding aerospace and industrial applications.

## Chemical Composition

The chemical composition of UNS N07090 plays a crucial role in its performance characteristics:

– Nickel (Ni): 55-59%
– Chromium (Cr): 18-21%
– Cobalt (Co): 12-15%
– Molybdenum (Mo): 3.5-5.0%
– Aluminum (Al): 1.2-1.6%
– Titanium (Ti): 2.75-3.25%
– Iron (Fe): ≤2.0%
– Carbon (C): ≤0.08%
– Boron (B): 0.003-0.010%
– Zirconium (Zr): 0.02-0.08%

## Mechanical Properties

UNS N07090 exhibits outstanding mechanical properties across a wide temperature range:

– Tensile Strength: 1,240 MPa (180 ksi) at room temperature
– Yield Strength: 830 MPa (120 ksi) at room temperature
– Elongation: 20% at room temperature
– Hardness: 36-40 HRC after heat treatment
– Creep Resistance: Excellent up to 870°C (1,600°F)

## Heat Treatment

Proper heat treatment is essential for achieving optimal properties in UNS N07090:

– Solution Treatment: 1,080°C (1,975°F) for 4 hours, air cool
– Aging Treatment: 845°C (1,550°F) for 4 hours, air cool + 760°C (1,400°F) for 16 hours, air cool

## Key Characteristics

UNS N07090 offers several advantageous properties:

– Excellent oxidation resistance up to 980°C (1,800°F)
– Outstanding creep-rupture strength
– Good fatigue resistance
– Superior corrosion resistance in various environments
– High strength-to-weight ratio
– Good fabricability and weldability

## Applications of UNS N07090

This nickel alloy finds extensive use in demanding applications:

### Aerospace Industry

– Turbine blades and disks
– Compressor components
– Jet engine parts
– Afterburner components
– Rocket motor cases

### Industrial Applications

– Gas turbine components
– High-temperature fasteners
– Nuclear reactor components
– Chemical processing equipment
– Oil and gas downhole tools

## Machining and Fabrication

While UNS N07090 can be machined, it requires special considerations:

– Use rigid machine setups and sharp cutting tools
– Employ positive rake angles and generous chip clearance
– Maintain moderate cutting speeds with heavy feed rates
– Use copious amounts of coolant
– Consider interrupted cuts to minimize work hardening

## Welding Considerations

UNS N07090 can be welded using several methods:

– Gas Tungsten Arc Welding (GTAW/TIG)
– Gas Metal Arc Welding (GMAW/MIG)
– Resistance Welding
– Electron Beam Welding

Post-weld heat treatment is typically required to restore optimal properties.

## Comparison with Other Nickel Alloys

Compared to similar nickel-based superalloys:

– Higher strength than Inconel 718 at elevated temperatures
– Better creep resistance than Hastelloy X
– Superior oxidation resistance compared to Rene 41
– More cost-effective than single-crystal superalloys for many applications

## Conclusion

Nickel Alloy UNS N07090 remains a critical material for high-temperature