Nickel alloys are alloys in which nickel is the main balancing element. Copper is completely soluble in nickel, while iron and chromium are soluble across a wide range of compositions, which allows many different alloys to be developed.
Nickel alloys generally combine excellent temperature resistance with strong corrosion resistance, so they tend to be used in the most aggressive environments and demanding applications.
Tradenames
As families of these alloys were developed by leading producers, they were marketed under a variety of tradenames. These names have gained common acceptance, even where the alloy is no longer produced by the trademark owner. They include Monel®, Incoloy® and Inconel® (Special Metals Inc), Hastelloy® (Haynes International Inc) and Invar (Arcelor Mittal).
Commonly used grades
The most commonly used nickel alloys include:
- Alloy 718 (Inconel 718, UNS N07718, 2.4668)
- Alloy 625 (Inconel 625, UNS N06625, 2.4856)
- Alloy 825 (Incoloy 825, UNS N08825, 2.4858)
- Alloy K500 (Monel K500, 2.4375)
Alloy 925 (Incoloy 925, UNS N09925) is increasing in popularity as a lower-cost alternative to Alloy 718. These grades are used predominantly in the oil and gas market, for a wide variety of components.
More highly alloyed, and more expensive, grades are used in the chemical process and pharmaceutical industries, where even greater resistance to acids and aggressive solutions is needed. These include Alloy C276 (Hastelloy C276, UNS N10276, 2.4819) and Alloy C22 (Hastelloy C22, UNS N06022, 2.4602).