Is Inconel the same as Alloy 625?
Alloy 625 and Alloy 718, commonly referred to as Inconel 625 and Inconel 718, are both nickel alloys, both are superalloys, and both are part of the Inconel family of alloys. So, what is the difference between Inconel 625 and 718?
What is the difference between Inconel 625 and 718?
We'll break down the differences between Inconel 625 and Inconel 718 below, from chemical composition to recommended uses. But first, let's talk terminology.
You may notice that we switch between Inconel 625 and Alloy 625 throughout this article. Rather than having you go and Google "Inconel 625 vs. Alloy 625" yourself, we wanted to explain what these names mean.
When we use the terms Inconel 625 and Alloy 625, we're referring to the same alloy. Inconel is a registered trademark of Special Metals Corporation. Therefore, for legal purposes, most alloy suppliers refer to it as Alloy 625 instead of Inconel 625.
Composition
The first major difference between Inconel Alloy 625 and 718 is their chemical composition. Both are nickel alloys, but each contains varying amounts of various chemicals that make them unique.
Alloy 625 is primarily nickel-based, while Alloy 718 is based on Nickel + Cobalt (Ni+Co). The use of Nickel + Cobalt in Alloy 718 means it has greater hardness and strength. Alloy 625, on the other hand, has higher levels of Chromium and Molybdenum, making it more corrosion resistant. See below for a full comparison of Inconel 625 vs. 718 chemical compositions.
Properties
Inconel 625 and Inconel 718 share many properties in common. Like most nickel alloys, both alloys offer high strength, ease of welding, and corrosion resistance.
However, the two alloys have different chemical compositions, which means they exhibit different levels of these properties. While both alloys are heat resistant, Alloy 718 has a higher melting range of 1321-1393°C. Likewise, while both alloys have good corrosion resistance, higher levels of chromium and molybdenum make Alloy 625 more corrosion resistant.
Applications
Inconel 625 and Inconel 718 are used in a range 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 of the aerospace industry. Its excellent heat resistance makes it ideal for high-temperature environments, including engine components. It is also used in high-performance automotive engines in the racing industry.
Product Forms
Alloys 625 and 718 are both easily formed and welded, so they are readily available in a variety of product forms.
Inconel 625 Product Forms
Tubes
Coil
Wire
Sheets
Round Bars
Fittings
Flanges
Inconel 718 Product Forms
Round Bars
Sheets
Wire
