What is the best Inconel alloy?
Inconel 625 and Inconel 718
Alloy 625 and Alloy 718, commonly referred to as Inconel 625 and Inconel 718, are both nickel alloys, both are high-temperature alloys, and both are part of the Inconel family of alloys. So, what's the difference between Inconel 625 and 718?
What is the difference between Inconel 625 and 718?
Below we break down the differences between Inconel 625 and Inconel 718, from chemical composition to recommended applications. But first, a word about terminology.
the term
You may notice that we switch between Inconel 625 and Alloy 625 throughout this article. Instead of asking you to Google "Inconel 625 vs. Alloy 625," we want to explain what these names mean.
When we use the terms Inconel 625 and Alloy 625, we are referring to the same alloy. Inconel is a registered trademark of Specialty Metals Corporation. Therefore, most alloy suppliers refer to it as Alloy 625 rather than Inconel 625 for legal purposes.
work
The first major difference between Inconel alloys 625 and 718 is their chemical composition. Both are nickel alloys, but each contains different amounts of various chemicals that differentiate them.
Alloy 625 is primarily a nickel-based alloy, while Alloy 718 is a nickel+cobalt (Ni+Co)-based alloy. The use of nickel + cobalt in Alloy 718 means it has greater hardness and strength. Alloy 625, on the other hand, has a higher chromium and molybdenum content, making it more corrosion-resistant. See a complete comparison of Inconel 625 vs. 718 chemical composition below.
characteristic
Inconel 625 and Inconel 718 share many characteristics. Like most nickel alloys, both are high-strength, easily weldable, and resistant to corrosion.
However, the different chemical compositions of the two alloys mean that they exhibit these properties to varying degrees. While both alloys are heat resistant, Alloy 718 has a higher melting range of 1321-1393°C. Likewise, while both exhibit good corrosion resistance, the higher levels of chromium and molybdenum make Alloy 625 more corrosion resistant.
application
Inconel 625 and Inconel 718 are suitable for a variety of industries and applications. However, their individual compositions and properties make each alloy excel in certain areas.
Inconel 625 Applications
Inconel 625 is most commonly used in the oil and gas industry due to its excellent corrosion resistance. This makes it the alloy of choice for subsea equipment. It is also used in corrosive environments in the aerospace industry, such as exhaust systems, furnaces and engine thrust reversers.
Inconel 718 Applications
Inconel 718 is a mainstay material in the aerospace industry. Its excellent heat resistance makes it ideal for applications in high temperature environments, including engine components. It is also used in high-performance automotive engines in the motorsports industry.
Product form
Alloys 625 and 718 are both easy to form and weld, so they are readily available in a variety of product forms.
