# UNS N07090 Alloy Properties and Applications

## Introduction to UNS N07090 Alloy

UNS N07090 is a nickel-based superalloy known for its exceptional high-temperature strength and corrosion resistance. This alloy is part of a family of materials designed to withstand extreme environments, making it a popular choice in aerospace, power generation, and chemical processing industries.

## Chemical Composition

The unique properties of UNS N07090 stem from its carefully balanced chemical composition:

Nickel (Ni): 50-55%

Chromium (Cr): 19-21%

Cobalt (Co): 15-21%

Molybdenum (Mo): 3-5%

Aluminum (Al): 1.4-1.8%

Titanium (Ti): 2.8-3.3%

Iron (Fe): ≤5%

## Mechanical Properties

### High-Temperature Performance

UNS N07090 maintains excellent mechanical strength at elevated temperatures up to 980°C (1800°F). Its creep resistance and stress rupture properties make it ideal for turbine applications where components are subjected to prolonged high-stress conditions.

### Room Temperature Properties

At ambient temperatures, UNS N07090 exhibits:

• Tensile strength: 1100-1300 MPa
• Yield strength: 750-900 MPa
• Elongation: 15-25%
• Hardness: 30-40 HRC

## Physical Properties

The physical characteristics of UNS N07090 include:

• Density: 8.19 g/cm³
• Melting range: 1290-1345°C
• Thermal expansion coefficient: 12.5 μm/m°C (20-100°C)
• Thermal conductivity: 11.4 W/m·K at 100°C

## Corrosion Resistance

Oxidation Resistance

UNS N07090 forms a protective chromium oxide layer that provides excellent oxidation resistance up to 1100°C. This makes it suitable for applications in oxidizing atmospheres.

Chemical Resistance

The alloy demonstrates good resistance to various corrosive media, including:

• Sulfuric acid
• Hydrochloric acid (diluted)
• Nitric acid
• Organic acids

## Heat Treatment

UNS N07090 typically undergoes the following heat treatment process:

1. Solution annealing at 1080-1120°C followed by rapid cooling
2. Aging treatment at 700-800°C for 16-24 hours

This treatment optimizes the precipitation of gamma prime phase (Ni3(Al,Ti)), enhancing the alloy’s mechanical properties.

## Fabrication and Machining

Forming

UNS N07090 can be hot worked in the temperature range of 1050-1200°C. Cold working is possible but requires intermediate annealing due to rapid work hardening.

Machining

The alloy is considered difficult to machine due to its high strength and work hardening tendency. Recommended practices include:

• Using rigid setups
• Sharp cutting tools with positive rake angles
• Slow speeds and heavy feeds
• Ample coolant application

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