Alloy 80A (UNS N07080) – High-Temperature Nickel-Chromium Alloy

# Alloy 80A (UNS N07080) – High-Temperature Nickel-Chromium Alloy

## Introduction to Alloy 80A

Alloy 80A, also known as UNS N07080, is a high-temperature nickel-chromium alloy that offers excellent resistance to oxidation and corrosion at elevated temperatures. This superalloy is widely used in applications requiring strength and durability in extreme environments.

## Chemical Composition

The chemical composition of Alloy 80A plays a crucial role in its performance characteristics:

– Nickel (Ni): 70-80%
– Chromium (Cr): 18-21%
– Aluminum (Al): 1.0-1.8%
– Titanium (Ti): 1.8-2.7%
– Iron (Fe): ≤ 3.0%
– Manganese (Mn): ≤ 1.0%
– Silicon (Si): ≤ 1.0%
– Copper (Cu): ≤ 0.5%
– Carbon (C): ≤ 0.1%

## Key Properties of Alloy 80A

Alloy 80A exhibits several remarkable properties that make it suitable for demanding applications:

### High-Temperature Strength

The alloy maintains excellent mechanical properties at temperatures up to 815°C (1500°F), making it ideal for high-stress applications in hot environments.

### Oxidation Resistance

The high chromium content provides outstanding resistance to oxidation and scaling at elevated temperatures.

### Creep Resistance

Alloy 80A demonstrates superior creep resistance under prolonged exposure to high temperatures and stresses.

### Corrosion Resistance

The nickel-chromium matrix offers good resistance to various corrosive environments, including sulfur-containing atmospheres.

## Mechanical Properties

The typical mechanical properties of Alloy 80A at room temperature include:

– Tensile Strength: 690-930 MPa (100-135 ksi)
– Yield Strength (0.2% offset): 310-620 MPa (45-90 ksi)
– Elongation: 30-50%
– Hardness: 150-250 HB

## Heat Treatment

Alloy 80A can be heat treated to optimize its mechanical properties:

### Solution Annealing

Typically performed at 980-1040°C (1800-1900°F) followed by rapid cooling to achieve maximum ductility.

### Aging Treatment

Aging at 700-760°C (1300-1400°F) for 16 hours can be applied to enhance strength properties.

## Fabrication and Processing

Alloy 80A can be processed using standard techniques:

### Machining

The alloy can be machined using conventional methods, though it work-hardens rapidly, requiring proper tool selection and cutting parameters.

### Welding

Alloy 80A is readily weldable using common techniques such as TIG, MIG, and resistance welding. Post-weld heat treatment is often recommended.

### Forming

The alloy can be hot or cold formed, though hot working is preferred for complex shapes due to its work-hardening characteristics.

## Applications of Alloy 80A

Alloy 80A finds extensive use in various industries:

### Aerospace Industry

– Turbine blades
– Combustion chamber components
– Exhaust systems

### Power Generation

– Gas turbine components
– Heat exchangers
– Boiler parts

### Chemical Processing

– Reactor vessels
– Piping systems
– Heat treatment fixtures

### Industrial Furnaces

– Retorts
– Furnace muffles
– Heat treating baskets

## Comparison with Similar Alloys

Alloy 80A is often compared with other nickel-chromium alloys:

### vs. Inconel 600

While both alloys offer good high-temperature properties, Alloy 80A has superior creep resistance due to its aluminum and titanium additions.

### vs. Inconel 601

Alloy 80A generally has better oxidation resistance at