In the world of high-performance nickel alloys, the Hastelloy name is synonymous with quality and durability. However, choosing the right grade for a demanding application is critical. Hastelloy C-276 and Hastelloy X are two of the most popular alloys, but they are engineered to excel in very different environments. One is a master of corrosion resistance, while the other is a champion of high-temperature strength.
This guide provides a detailed comparison of Hastelloy C-276 vs Hastelloy X to help you select the correct material for your project.
What is Hastelloy C-276?
Hastelloy C-276 is a nickel-molybdenum-chromium-tungsten alloy known for its outstanding corrosion resistance in a wide range of severe environments. It is one of the most versatile corrosion-resistant alloys available, effective against both oxidizing and reducing media. Its primary design purpose is to withstand the most aggressive chemical attacks, making it a staple in the chemical processing and pollution control industries.
Key Characteristics of Hastelloy C-276:
- Exceptional resistance to pitting, crevice corrosion, and stress-corrosion cracking.
- Excellent resistance to strong oxidizing chlorides and wet chlorine gas.
- Superior performance in mixtures of contaminated acids (such as sulfuric and hydrochloric acid).
What is Hastelloy X?
Hastelloy X is a nickel-chromium-iron-molybdenum alloy that is part of the superalloy family. Its primary strength is its exceptional performance at extremely high temperatures. It is a solid-solution-strengthened alloy that offers a remarkable combination of high strength, outstanding oxidation resistance, and excellent fabricability. It is the go-to material for components in the hottest sections of gas turbines and industrial furnaces.
Key Characteristics of Hastelloy X:
- Outstanding high-temperature strength and creep-rupture properties.
- Exceptional resistance to oxidation at temperatures up to 1200°C (2200°F).
- Excellent fabricability, particularly weldability, for a superalloy.
Key Difference: Chemical Composition
The fundamental difference between these two alloys lies in their chemical composition, which dictates their primary strengths. Hastelloy C-276 is optimized with high molybdenum and tungsten for corrosion resistance, while Hastelloy X uses high chromium and iron for high-temperature stability.
| Element | Hastelloy C-276
(Weight %) |
Hastelloy X
(Weight %) |
| Nickel (Ni) | 54.0 – 58.0 | 45.0 – 55.0 |
| Molybdenum (Mo) | 15.0 – 17.0 | 8.0 – 10.0 |
| Chromium (Cr) | 14.5 – 16.5 | 20.5 – 23.0 |
| Iron (Fe) | 4.0 – 7.0 | 17.0 – 20.0 |
| Tungsten (W) | 3.0 – 4.5 | 0.2 – 1.0 |
| Cobalt (Co) | 2.5 max | 0.5 – 2.5 |
| Carbon © | 0.010 max | 0.05 – 0.15 |
| Manganese (Mn) | 1.0 max | 1.0 max |
| Silicon (Si) | 0.08 max | 1.0 max |
Key Difference: Performance and Properties
The variation in composition directly translates to distinct performance characteristics for each alloy.
| Property | Hastelloy C-276 | Hastelloy X |
| Corrosion Resistance | Exceptional. The benchmark for severe chemical environments. | Good, but not designed for aggressive corrosion. |
| High-Temp. Strength | Good, but loses strength rapidly above 650°C. | Exceptional. Maintains strength up to ~1200°C. |
| Oxidation Resistance | Good up to ~1095°C. | Exceptional. Forms a highly protective, adherent oxide scale. |
| Primary Design Goal | Resisting corrosive chemicals. | Resisting extreme heat and oxidation. |
Application Comparison
Choose Hastelloy C-276 for applications where:
- Corrosion is the primary concern.
- The environment involves aggressive acids, chlorides, or oxidizing agents.
- Components like pumps, valves, and piping systems are exposed to harsh chemicals.
Common Hastelloy C-276 Applications:
- Chemical and petrochemical processing equipment.
- Pulp and paper bleaching plants.
- Flue gas desulfurization (FGD) systems.
- Pharmaceutical and food processing equipment.
Choose Hastelloy X for applications where:
- Extreme high-temperature strength and oxidation are the primary concerns.
- The component is exposed to sustained heat and thermal cycling.
- Fabricability, especially welding, is a critical requirement for a high-temp alloy.
Common Hastelloy X Applications:
- Gas turbine engine combustors, transition ducts, and afterburners.
- Industrial furnace components like baskets, trays, and retorts.
- Heat-treating equipment and furnace hardware.
- Aircraft engine thrust reversers.
Conclusion
While both are premium Hastelloy alloys, C-276 and X are specialists for different challenges. Hastelloy C-276 is the ultimate solution for combating severe corrosion, while Hastelloy X is the workhorse for surviving extreme heat. By matching the alloy’s core strength to your application’s most demanding condition, you guarantee performance, safety, and longevity.
If you need assistance selecting the right material or require a competitive quote for your project, contact Daxun Alloys Co., Ltd. We are experts in high-performance nickel alloys. We supply both Hastelloy C-276 and Hastelloy X in various forms, including plate, sheet, bar, and pipe.Our material experts are ready to provide the guidance and support you need.
Information reference source:
HASTELLOY® C-276: https://haynesintl.com/en/alloys/alloy-portfolio/corrosion-resistant-alloys/hastelloy-c-276/
HASTELLOY® X: https://haynesintl.com/en/alloys/alloy-portfolio/high-temperature-alloys/hastelloy-x/
