In industrial projects, the material chosen is as important as the design. Two common alloys are Inconel 625 and Inconel 825 alloys. Let’s compare these two materials so you can make an informed decision for your project.
Inconel 625 and Inconel 825 are nickel-based superalloys developed by Special Metals Corporation, and like most superalloys, both have excellent corrosion resistance and high-temperature strength. However, there are some differences between them to keep in mind when choosing which alloy to use for your project.
Performance
The main difference between alloy Inconel 625 and alloy Inconel 825 is the performance at elevated temperatures. alloy Inconel 625 has a higher melting point than alloy Inconel 825, 2000°F (1093°C) and 1742°F (950°C) respectively. This means that alloy Inconel 625 has a longer lasting strength at high temperatures than alloy Inconel 825. However, Inconel 825 alloy has superior stress fracture strength – that is, the ability to resist cracking under cyclic loading at temperatures up to 1200°F (649°C).
Applications
In terms of applications, the two alloys have some similarities, but also some significant differences. Both alloys are used in chemical processing equipment such as heat exchangers, pumps and valves; they are also used in petroleum refining equipment and other industrial components exposed to high temperatures and corrosive environments. However, because of its higher melting point and superior stress-break strength at elevated temperatures, alloy Inconel 625 is typically used in more demanding applications such as gas turbines and nuclear reactors, while alloy Inconel 825 is often used in less demanding applications such as exhaust manifolds and chemical processing equipment.
Chemical Composition
Alloy Inconel 625 is an austenitic nickel-chromium-molybdenum alloy containing 9 per cent nickel, 22 per cent chromium, 3 per cent molybdenum and small amounts of manganese, silicon, iron and carbon.Alloy Inconel 825 is an austenitic nickel-iron-chromium alloy containing 38 per cent nickel, 20 per cent iron, 2.5 per cent chromium and small amounts of manganese, silicon, copper and titanium.
Tensile strength
One of the most important properties of any material is its tensile strength, i.e. the ability of a material to resist being stretched by a force. Inconel 625 alloy has a tensile strength of 125 ksi (862 MPa), while Inconel 825 alloy has a tensile strength of 100 ksi (690 MPa).
Yield strength
The yield strength of a material is the stress at which it begins to deform plastically. This is important for materials that will be used in structures or other applications that will be subjected to loads that may cause them to yield. Inconel 625 alloy has a yield strength of 95 ksi (655 MPa), while Inconel 825 alloy has a yield strength of 75 ksi (517 MPa).
Elongation
Elongation is a measure of a material’s ability to deform before breaking. This property is important for materials that will be subjected to loads that may cause them to deform significantly before rupture. Inconel 625 alloy has an elongation of 30%, while Inconel 825 alloy has an elongation of 20%.
Density
The density of a material is the mass per unit volume. This property is important for many applications where weight and/or space are considerations. Inconel 625 alloy has a density of 0.305 pounds per cubic inch (8.44 grams per cubic centimetre), while Inconel 825 alloy has a density of 0.292 pounds per cubic inch (8.08 grams per cubic centimetre).
Overall, the choice between alloy Inconel 625 or Inconel 825 depends on your specific application. If you need higher high-temperature strength and a more demanding application, alloy Inconel 625 may be the better choice. If your application scenario is relatively lightweight and requires better corrosion resistance, Inconel 825 alloy may be a better choice. Of course, you should also consider other factors such as the cost and availability of the material to make your final decision.
Post time: Jul-22-2023
