Alloys have always been a significant part of industrial applications due to their unique and superior properties. This article aims to provide an in-depth comparison of two such alloys that are highly popular in numerous industries: Inconel 625 and Hastelloy C276. Our discussion will delve deep into their chemical composition, corrosion resistance, mechanical behavior, physical properties, applications, and pricing.
Basic Information
When it comes to Inconel 625 vs Hastelloy C276, both are nickel-chromium-molybdenum-based alloys with excellent corrosion resistance and high strength. However, they have different concentrations of chromium and molybdenum, which makes them suitable for various environments.
Inconel 625
Inconel 625, characterized by the brand INCONEL® and the matrix Nickel Chromium Molybdenum Niobium, is a solid solution strengthened alloy. With a density of 8.44 g/cm³, it is suitable for high-temperature applications. Its UNS number is N06625, and its W.Nr. number is 2.4856.
Hastelloy C-276
Hastelloy C-276, under the brand HASTELLOY®, is also a solid solution strengthened alloy with Nickel Chromium Molybdenum as its matrix. This alloy has a higher density of 8.89 g/cm³ and is also suitable for high-temperature applications. Its UNS number is N10276, and its W.Nr. number is 2.4819.
Chemical Composition
While both Inconel 625 and Hastelloy C-276 have high nickel and iron content, they differ significantly in their chromium and molybdenum content, impacting their corrosion resistance.
Inconel 625
Inconel 625 contains more chromium than Hastelloy C-276. Chromium enhances the oxidation resistance of the alloy, making Inconel 625 more resistant to corrosive environments, particularly oxidizing environments like concentrated sulfuric acid and nitric acid.
Hastelloy C-276
Hastelloy C-276, on the other hand, contains more molybdenum than Inconel 625. Molybdenum plays a crucial role in anti-reduction, making this alloy perform better in reducing environments such as hydrochloric acid and hydrogen sulfuric acid.
Corrosion Resistance
In the battle of Inconel 625 vs Hastelloy C276, both alloys show great promise in terms of corrosion resistance.
Inconel 625
Inconel 625 exhibits better corrosion resistance in oxidizing environments due to its higher chromium content. It is capable of withstanding concentrated sulfuric acid, nitric acid, and similar corrosive substances.
Hastelloy C-276
Hastelloy C-276, with its higher molybdenum content, shows excellent performance in reducing environments. It can withstand corrosive substances like hydrochloric acid and hydrogen sulfuric acid.
Mechanical Behavior
Both Inconel 625 and Hastelloy C-276 are solid solution strengthened alloys. However, they utilize different solid solution strengthening elements, impacting their mechanical properties.
Inconel 625
Inconel 625 contains niobium and tantalum, both known for their excellent solid solution strengthening effect. This combination provides Inconel 625 with impressive strength.
Hastelloy C-276
Hastelloy C-276 relies mainly on tungsten and molybdenum for solid solution strengthening. The large atomic radii of these elements make their strengthening effect on Hastelloy C-276 quite pronounced.
Physical Properties
The physical properties of these alloys also play a significant role in their application.
Inconel 625
Inconel 625 has a density of 8.44 g/cm³ and a melting range of 2350-2460°F (1290-1350°C).
Hastelloy C-276
Hastelloy C-276 has a slightly higher density of 8.89 g/cm³ and a melting range of 2415-2500°F (1323-1371°C).
Application
Both alloys find use in a wide range of applications, with their application range being very close to a large extent. However, this doesn’t mean that these alloys can substitute each other in all situations. The application environment dictates the choice of the alloy. For instance, in oil and gas applications, Inconel 625 is more suitable for oxidizing environments, while Hastelloy C-276 should be used for reducing environments.
Main Standards
Inconel 625 and Hastelloy C-276 have different standards for various products.
Inconel 625
Inconel 625 standards include: Seamless Pipe and Tube: ASTM B444, ASTM B829; Welded Pipe: ASTM B705, ASTM B775; Welded Tube: ASTM B704, ASTM B751; Welded Fittings: ASTM B366; Rod and Bar: ASTM B446; Forgings: ASTM B564; Plate, Sheet, and Strip: ASTM B443.
Hastelloy C-276
Hastelloy C-276 standards include: Seamless Pipe and Tube: ASTM B622, ASTM B983; Welded Pipe: ASTM B619; Welded Tube: ASTM B626; Fittings: ASTM B366, ASTM B462; Billet, Rod and Bar: ASTM B574; Forgings: ASTM B564, ASTM B462; Plate, Sheet, and Strip: ASTM B575.
Price
Generally, the price of molybdenum is slightly higher than that of chromium. Hence, Hastelloy C-276 tends to be a bit more expensive compared to Inconel 625. However, overall, their prices don’t vary significantly.
Conclusion
In the comparison of Inconel 625 vs Hastelloy C276, both alloys demonstrate good corrosion resistance. Inconel 625 is more suitable for oxidizing environments, while Hastelloy C-276 is more apt for reducing environments. Although the solid solution strengthening elements differ, the mechanical properties of both alloys are fairly similar. The application ranges of the two alloys are similar, but they play different roles within the same application.
While making a choice between the two, it is crucial to consider the specific requirements of your application. Both Inconel 625 and Hastelloy C-276 are robust and reliable choices, each with their unique advantages and characteristics.
For more information on these alloys or if you have specific requirements, feel free to contact us. We are always here to help you make the most informed decisions.
