Hastelloy X (UNS N06002) High-Temperature Nickel Alloy

# Hastelloy X (UNS N06002) High-Temperature Nickel Alloy

## Introduction to Hastelloy X

Hastelloy X, also known as UNS N06002, is a nickel-chromium-iron-molybdenum alloy renowned for its exceptional high-temperature strength and oxidation resistance. This superalloy is widely used in extreme environments where other materials would fail, making it a critical component in industries such as aerospace, power generation, and chemical processing.

## Composition and Properties

The chemical composition of Hastelloy X contributes to its remarkable performance:

– Nickel (Ni): 47% (base)
– Chromium (Cr): 22%
– Iron (Fe): 18%
– Molybdenum (Mo): 9%
– Cobalt (Co): 1.5%
– Tungsten (W): 0.6%
– Carbon (C): 0.10%

This unique combination of elements gives Hastelloy X several key properties:

– Excellent oxidation resistance up to 2200°F (1204°C)
– Outstanding high-temperature strength
– Good fabricability and weldability
– Resistance to stress-corrosion cracking
– Good ductility and toughness

## Applications of Hastelloy X

Due to its exceptional properties, Hastelloy X finds applications in numerous demanding environments:

### Aerospace Industry

Hastelloy X is extensively used in aircraft gas turbine engines for components such as combustion chambers, afterburners, and transition ducts. Its ability to withstand extreme temperatures and corrosive environments makes it ideal for these critical applications.

### Industrial Furnaces

The alloy is commonly employed in industrial furnace components, including radiant tubes, muffles, and retorts, where it maintains structural integrity under continuous high-temperature operation.

### Chemical Processing

In chemical plants, Hastelloy X is used for equipment handling corrosive media at elevated temperatures, such as reactors, heat exchangers, and piping systems.

## Fabrication and Welding

Hastelloy X can be readily fabricated using standard techniques:

– Hot working should be performed between 2100-2250°F (1149-1232°C)
– Cold working requires intermediate annealing
– Welding can be done using gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW)
– Post-weld heat treatment is generally not required

## Comparison with Other High-Temperature Alloys

When compared to similar high-temperature alloys, Hastelloy X offers:

– Better oxidation resistance than Inconel 600
– Superior strength at high temperatures compared to 310 stainless steel
– Better fabricability than some cobalt-based superalloys
– More cost-effective than many specialized nickel alloys

## Maintenance and Care

To ensure optimal performance of Hastelloy X components:

– Avoid contamination during fabrication and handling
– Clean surfaces thoroughly before welding
– Store in dry environments to prevent surface oxidation
– Follow recommended heat treatment procedures when required

Hastelloy X (UNS N06002) remains one of the most versatile and reliable high-temperature nickel alloys available today. Its combination of strength, oxidation resistance, and fabricability makes it an excellent choice for applications where other materials would fail under extreme conditions. As technology advances and operating temperatures continue to increase in various industries, the demand for this remarkable alloy is likely to grow even further.