Hastelloy C-22 and Hastelloy C-276 are both high-performance alloys, which are widely used in corrosive applications in extreme environments. They play a crucial role in industries such as chemical processing, marine engineering, and oil and gas.
For those familiar with nickel-based alloys, it’s well-known that both Hastelloy C-22 and Hastelloy C-276 are nickel-chromium-molybdenum alloys. However, you might be curious about the specific differences between them and why Hastelloy C-276 is more commonly used than Hastelloy C-22.
This article will provide an in-depth comparison of Hastelloy C-22 and Hastelloy C-276, exploring their similarities and differences in chemical composition, mechanical properties, corrosion resistance, and application areas. By examining these properties, you’ll gain a better understanding of how to choose between these two alloys and how to leverage their characteristics to ensure the reliability and performance of your equipment.
Keep reading to learn more.
HASTELLOY® C-22® alloy (UNS N06022) is one of the well-known and well-proven nickel-chromium-molybdenum materials, the chief attributes of which are resistance to both oxidizing and non-oxidizing chemicals, and protection from pitting, crevice attack, and stress corrosion cracking.
What is Hastelloy Alloy C-276?
HASTELLOY® C-276 alloy (UNS N10276) was the first wrought, nickel-chromium-molybdenum material to alleviate concerns over welding (by virtue of extremely low carbon and silicon contents). As such, it was widely accepted in the chemical process and associated industries, and now has a 50-year-old track record of proven performance in a vast number of corrosive chemicals.
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Chemical Composition
Here’s a comparison table for the chemical composition of Hastelloy C-22 and Hastelloy C-276:
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Corrosion Resistance
The primary distinction between Hastelloy C-22 and Hastelloy C-276 lies in their corrosion resistance. Despite both being nickel-chromium-molybdenum alloys, their elemental ratios differ.
Hastelloy C-22 contains higher chromium and lower molybdenum compared to Hastelloy C-276. Consequently, Hastelloy C-22 offers superior oxidation resistance, while Hastelloy C-276 excels in reduction resistance.
Additionally, Hastelloy C-22 has better control over trace elements, providing enhanced resistance to crevice corrosion at high temperatures compared to Hastelloy C-276.
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Mechanical Behavior
Hastelloy C-22 and Hastelloy C-276 are both solid solution alloys with well-balanced mechanical properties. They both achieve significant strength through solid solution strengthening with molybdenum and tungsten.
That said, Hastelloy C-22 generally has slightly superior mechanical properties compared to Hastelloy C-276. This is primarily due to its stricter control of harmful elements, which enhances purity and is particularly evident in its higher yield strength. Additionally, Hastelloy C-22 exhibits better plasticity than Hastelloy C-276.
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Physical Properties
| Hastelloy C-22 | Hastelloy C-276 | |
|---|---|---|
| Density, g/cm³ | 8.69 | 8.89 |
| Density, lb/in.³ | 0.314 | 0.321 |
| Melting Range, °F | 2475-2550 | 2415-2500 |
| Melting Range, °C | 1357-1399 | 1323-1371 |
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Applications
Like other nickel alloys, HASTELLOY® C-22® alloy is very ductile, exhibits excellent weldability, and is easily fabricated into industrial components. It is available in the form of plates, sheets, strips, billets, bars, wires, pipes, tubes, and covered electrodes. Typical chemical process industry (CPI) applications include reactors, heat exchangers, and columns.
Hastelloy C-276 has demonstrated exceptional ability to resist seawater corrosion. Sea water is the most common salt water solution. It is widely used in marine and offshore oil rigs and as a coolant in coastal installations.
Hastelloy C-22 and Hastelloy C-276 have very similar application ranges. In practical use, it is important to consider specific details, such as the material’s working environment. Selecting the appropriate material depends on the particular corrosive substances it will encounter.
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Main Standards
Here’s a comparison table for the standards of Hastelloy C-22 and Hastelloy C-276:
Hastelloy Alloy C-22 vs Hastelloy Alloy C-276 Cost
The price of Hastelloy C-22 is higher compared to Hastelloy C-276.
Firstly, Hastelloy C-22 demands stricter control of trace elements, necessitating the use of higher purity metal raw materials during smelting. This inherently increases the cost.
Secondly, Hastelloy C-276 is produced in larger quantities, benefiting from economies of scale. In contrast, Hastelloy C-22 is less common, making customization more expensive.
As a result, despite Hastelloy C-276 containing more costly elements like molybdenum and tungsten, it remains less expensive than Hastelloy C-22.
Conclusion
Hastelloy C-22 and Hastelloy C-276 are both nickel-chromium-molybdenum alloys, with the primary difference being their chromium and molybdenum content.
Due to this difference, Hastelloy C-22 is more suitable for oxidative corrosive environments, while Hastelloy C-276 is better suited for reducing environments.
Both alloys offer excellent overall corrosion resistance. Additionally, Hastelloy C-22 has stricter controls on harmful elements, providing better performance at high temperatures. Hastelloy C-276, being relatively cheaper, is more widely used.
We manufacture a variety of products using Hastelloy C-22 and Hastelloy C-276 in strict accordance with industry standards. For any purchasing needs, please contact our expert team for assistance.
