There are many different varieties of Inconel's, each has a different composition, but all are generally nickel, with chromium as the second element.
Inconel alloys are corrosion and oxidation resistant and therefore are well suited for usage in extreme environments. When heat is applied to Inconel it forms a protective oxide layer through passivation. Inconel retains strength over a wide temperature range, an advantage for high temperature applications. Depending on the alloy, Inconel's high temperature strength is established either by solid solution strengthening or precipitation strengthening.
Inconel is a difficult metal to shape and machine using traditional techniques due to rapid work hardening.
Inconel alloys are generally known for their resistance to oxidation and their ability to maintain their structural integrity in high temperature atmospheres.
While each variation of Inconel has unique traits that make it effective in different circumstances, the majority of the alloys are used frequently in the chemical industry. Inconel 601 is a nickel-chromium alloy that has additions of aluminum. These additions increase its resistance to oxidation and various forms of corrosion. This has made Inconel 601 a common material in heat treating equipment, furnaces, and gas-turbine components. The high chromium content in 690 makes it especially resistant to corrosion that occurs from salts, oxidizing acids, and other elements commonly found in aqueous environments.
Inconel 601
Like Inconel 600, Inconel 601 offers resistance to various forms of high-temperature corrosion and oxidization. However, unlike 600, this nickel-chromium alloy has an addition of aluminum. This addition allows it to demonstrate high mechanical properties even in extremely hot environments. Inconel 601's ability to stave off the strain that would result in many alloys when exposed to high temperatures has led to its use in furnaces and heat treating equipment like retorts and baskets
Inconel 625
Inconel 625 differs from many of the other Inconel alloys because its composition includes substantial amounts of nickel, chromium, and molybdenum. It also has an addition of niobium. The result is an alloy that possesses high levels of strength without ever having to go through a strengthening heat treatment. Inconel 625 is especially effective at resisting crevice corrosion, making it a chosen material in the aerospace and marine engineering industries.
Inconel 690
Inconel 690 contains high-chromium and nickel alloy. The high-chromium element of the alloy gives it a particularly strong resistance to corrosion that occurs in aqueous atmospheres and can endure the sulfidation that takes place at high temperatures. Due to anticorrosive properties 690 enjoys strong metallurgical stability which allows it to retain structural integrity in various applications.
Inconel 718
Inconel 718 has high levels of iron, molybdenum, and niobium as well as traces of titanium and aluminium. Inconel 718 is designed to provide a high level of strength and flexibility, this allows it to be particularly resistant to post-weld cracking. Well suited to both high-temperature and aqueous environments.
Inconel 722
Inconel 722 is a nickel-chromium alloy that shares many of the same properties as other Inconel alloys. Inconel 722 can withstand the stress caused by several types of acids, which has made it popular in the chemical industry.