Both Inconel 625 and Hastelloy C-276 are nickel-chromium-molybdenum-based alloys renowned for their outstanding corrosion resistance and high strength.
Inconel 625 has a higher chromium content, while Hastelloy C-276 contains more molybdenum. These variations affect their performance in different corrosive environments.
This article will offer a comprehensive comparison of these two alloys from multiple perspectives, helping you make an informed decision for your upcoming project.
Let’s keep reading.
What is Inconel Alloy 625?
INCONEL® nickel-chromium alloy 625 (UNS N06625 / W.Nr. 2.4856) is used for its high strength, excellent fabricability (including joining), and outstanding corrosion resistance. Service temperatures range from cryogenic to 1800°F (982°C).
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.
Inconel Alloy 625 vs Hastelloy Alloy C-276 Chemical Composition
Here’s a comparison table for the chemical composition of Inconel 625 and Hastelloy alloy C-276:
Inconel Alloy 625 vs Hastelloy Alloy C-276 Corrosion Resistance
The nickel and iron content in Inconel 625 and Hastelloy C-276 are very similar, with the primary differences being in their chromium and molybdenum content.
Inconel 625 has a higher chromium content, which enhances its oxidation resistance. This makes it more effective in oxidizing environments, such as concentrated sulfuric acid and nitric acid.
On the other hand, Hastelloy C-276 contains more molybdenum, which provides excellent resistance to reducing environments like hydrochloric acid and hydrogen sulfide. This gives Hastelloy C-276 superior performance in such conditions.
Inconel Alloy 625 vs Hastelloy Alloy C-276 Mechanical Behavior
Inconel 625 and Hastelloy C-276 are both solid solution strengthened alloys, exhibiting similar mechanical properties with differences in their primary strengthening elements.
Inconel 625 contains niobium and tantalum, which provide excellent solid solution strengthening, contributing to its high strength. Additionally, although typically not subjected to aging treatment, the small amount of precipitation strengthening from niobium and tantalum further enhances the alloy’s strength.
Hastelloy C-276, in contrast, relies on tungsten and molybdenum for solid solution strengthening. Due to their large atomic radii, tungsten and molybdenum significantly strengthen Hastelloy C-276.
Inconel Alloy 625 vs Hastelloy Alloy C-276 Physical Properties
| Inconel 625 | Hastelloy C-276 | |
|---|---|---|
| Density, g/cm³ | 8.44 | 8.89 |
| Density, lb/in.³ | 0.305 | 0.321 |
| Melting Range, °F | 2350-2460 | 2415-2500 |
| Melting Range, °C | 1290-1350 | 1323-1371 |
Inconel Alloy 625 vs Hastelloy Alloy C-276 Applications
Due to its excellent corrosion resistance, a typical application of Inconel 625 is marine. Its resistance to localized corrosion (pitting and crevice corrosion), chloride ion stress corrosion, and its excellent fatigue strength make it widely used in marine parts such as propeller blades, exhaust pipes, and fasteners. For ambient temperature applications, Inconel 625 is recommended to be delivered annealed.
In addition, Inconel 625 is also widely used in the aerospace field, thanks to its excellent high-temperature tensile properties and creep strength. Through processing and welding, Inconel 625 can be used in components such as aircraft piping systems, engine exhaust systems, fuel and hydraulic lines, and heat exchanger tubes. The high temperature properties of Inconel 625 alloy also make it used in heat treatment equipment and chemical industry.
Hastelloy C-276 is ideal for marine applications. Its corrosion resistance makes it resistant to various corrosive substances in flowing seawater for a long time. However, Hastelloy C-276 also has good overall performance at high temperatures. It is very suitable for the preparation equipment of various corrosive chemicals or the reactor of various acidic substances.
Inconel Alloy 625 vs Hastelloy Alloy C-276 Main Standards
Here’s a comparison table for the standards of Inconel alloy 625 and Hastelloy alloy C-276:
Inconel Alloy 625 vs Hastelloy Alloy C-276 Price
Generally speaking, the price of molybdenum will be a little higher than that of chromium, so the price of Hastelloy C-276 will be slightly higher. But overall, their prices are not much different.
Conclusion
Both Inconel 625 and Hastelloy C-276 offer exceptional corrosion resistance, with Inconel 625 being more suitable for oxidizing environments and Hastelloy C-276 excelling in reducing environments.
These alloys are solid solution strengthened, with different elements contributing to this effect. Despite the variation in strengthening elements, their overall mechanical properties are quite similar.
Although the application ranges of Inconel 625 and Hastelloy C-276 overlap, each alloy has distinct strengths within the same applications.
HZW can produce Inconel 625 and Hastelloy C-276 alloy products tailored to your specific requirements. If you have purchasing needs, please contact our team.
