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

## Introduction to Alloy 80A

Alloy 80A, also known by its UNS designation 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%
– Carbon (C): ≤ 0.10%
– Manganese (Mn): ≤ 1.0%
– Silicon (Si): ≤ 1.0%
– Copper (Cu): ≤ 0.5%

## 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-temperature applications.

### Oxidation Resistance

The high chromium content provides outstanding resistance to oxidation in both continuous and intermittent service at elevated temperatures.

### Creep Resistance

Alloy 80A demonstrates superior creep resistance, which is critical for components subjected to long-term stress at high temperatures.

### Corrosion Resistance

The alloy offers good resistance to various corrosive environments, including sulfur-containing atmospheres.

## Heat Treatment

Proper heat treatment is essential for optimizing the properties of Alloy 80A:

– Solution Annealing: Typically performed at 1080-1120°C (1975-2050°F) followed by rapid cooling
– Aging: Often carried out at 700-760°C (1290-1400°F) for 16 hours to achieve optimal properties

## Mechanical Properties

The mechanical properties of Alloy 80A vary depending on heat treatment and temperature:

### Room Temperature Properties

– Tensile Strength: 900-1200 MPa (130-175 ksi)

– Yield Strength: 600-900 MPa (85-130 ksi)
– Elongation: 15-30%
– Hardness: 25-35 HRC

### Elevated Temperature Properties

The alloy maintains significant strength at high temperatures, with tensile strength values of approximately 600 MPa (87 ksi) at 700°C (1290°F).

## Applications of Alloy 80A

Alloy 80A finds extensive use in various industries due to its exceptional properties:

### Aerospace Industry

– Turbine blades
– Combustion chambers
– Afterburner components

### Power Generation

– Gas turbine components
– Heat exchangers
– Boiler parts

### Chemical Processing

– Reactor vessels
– Heat treatment fixtures
– Furnace components

### Oil and Gas

– Downhole tools
– Wellhead components
– Valve parts

## Fabrication and Welding

Alloy 80A can be fabricated using standard techniques, though some considerations apply:

### Machining

The alloy is more difficult to machine than conventional steels but can be successfully machined using appropriate techniques and tooling.

### Welding

Alloy 80A is readily weldable using conventional methods:

– Gas tungsten arc welding (GTAW/TIG)
– Gas metal arc welding (GMAW/MIG)
– Shielded metal arc welding (SMAW)

Post-weld heat treatment is often recommended to restore optimal properties in the heat-affected zone.

## Comparison with Similar Alloys

Alloy 80A is often compared with other high-temperature alloys:

### Alloy 80