What is the Difference Between Inconel 625 and 825?

Inconel 625 and Inconel 825 are both nickel-based superalloys, but they have some differences in their composition, performance, and applications. Here are the main differences between the two:

1. Nickel Content: Inconel 625 contains about 58% nickel, while Inconel 825 contains about 36-48% nickel.
2. Melting Point: Inconel 625 has a higher melting point (2000°F or 1093°C) compared to Inconel 825 (1742°F or 950°C).
3. High-Temperature Strength: Inconel 625 has a longer-lasting strength at high temperatures due to its higher melting point.
4. Stress Fracture Strength: Inconel 825 has superior stress fracture strength, meaning it can resist cracking under cyclic loading at temperatures up to 1200°F (649°C) better than Inconel 625.
5. Tensile and Yield Strength: Inconel 625 has higher tensile strength and yield strength compared to Inconel 825.
6. Elongation: Inconel 625 has a lower elongation than Inconel 825.
7. Corrosion Resistance: Inconel 625 exhibits strong corrosion resistance, particularly in oxidizing and reducing acidic environments.
8. Applications: Inconel 625 is commonly used in aerospace, chemical processing, marine, oil & gas, petro processing, pollution & waste, and power applications. Inconel 825 is also used in various industrial applications, but it is often preferred when cost is a more significant factor.

In summary, Inconel 625 is a more expensive alloy with higher high-temperature strength, tensile strength, and yield strength, making it suitable for demanding applications. Inconel 825 is a more cost-effective alternative with superior stress fracture strength and corrosion resistance, making it suitable for lighter applications. The choice between Inconel 625 and Inconel 825 depends on the specific requirements of the application, considering factors such as performance, cost, and material availability.

Comparative Table: Inconel 625 vs 825

Inconel 625 and Inconel 825 are both nickel-based superalloys with excellent corrosion resistance and high-temperature strength. However, there are some differences between them:

Inconel 625 has a higher nickel content compared to Inconel 825, which contributes to its higher tensile strength and better corrosion resistance properties. Inconel 825 has a higher iron content, which reduces the cost of the alloy but also reduces its corrosion resistance. The melting point of Inconel 625 is 1350°C, while Inconel 825 has a melting point of 1400°C. Both alloys have a broad range of applications, including aerospace, chemical processing, marine, oil & gas, petrochemical, and power industries.