Introduction
Nickel-based alloys have been in existence since the second half of the 19th century. Since then, these alloys have been known for their high strength, excellent corrosion resistance, and unique thermal and electrical properties. These alloys are mainly used for many challenging applications. Nickel-based alloys are primarily divided into four categories: heat-resistant alloys, high-temperature alloys, corrosion-resistant alloys, and superalloys. Heat-resistant alloys are used at temperatures up to approximately 1000°C. High-temperature alloys can be used at temperatures between 900°C and 1300°C. Corrosion-resistant alloys are used in places where there are frequent corrosive atmospheres. Superalloys are alloys that are made of several metals and can sustain their mechanical and physical properties at extreme temperatures.
Classification of Nickel-based Alloys
Most nickel-based alloys are classified into three groups, which are based on the amount of nickel used in the alloy. These three classes are known as nickel steels, high-nickel alloys, and superalloys.
Nickel steels are alloys that contain less than 30 percent nickel content. These alloys are primarily used for applications that require good corrosion resistance. Nickel steels are further divided into various groups depending on the amount of nickel content. Examples of these alloys include Monel, Inconel, Incoloy, and Hastelloy.
High-nickel alloys are alloys that contain higher amounts of nickel, which range from approximately 30 to 75 percent nickel content. These alloys are primarily used for their high strength and excellent corrosion resistance. Examples of these alloys include Hastelloy X, Inconel 718, and Waspaloy.
Superalloys are alloys with a nickel content greater than 75 percent. These alloys are mainly used in applications where there are extreme temperatures and stresses. Examples of superalloys include Inconel 722, Inconel X-750, and Waspaloy.
Properties of Nickel-based Alloys
Nickel-based alloys have many desirable properties that make them a great choice for various applications. These alloys have good strength, hardness, corrosion resistance, and creep resistance.
The strength of these alloys is determined by the amount of nickel and other elements used in the alloy. The higher the nickel content in the alloy, the stronger the alloy will be. Additionally, these alloys can be strengthened by cold working and heat treating.
Nickel-based alloys also have excellent corrosion resistant properties. This is due to the ability of the alloy to form an oxide layer on its surface which prevents the corrosion process. Furthermore, these alloys also have good creep resistance, meaning they can withstand high temperatures and stresses without being damaged.
Applications of Nickel-based Alloys
Nickel-based alloys are used in a variety of applications due to their desirable properties. These alloys are primarily used in applications requiring high strength and corrosion resistance, such as for marine environments, chemical processing, and nuclear reactors.
Nickel-based alloys are also often used for fasteners, bolts, pressurized tanks, piping systems, heat exchangers, and pressure vessels. The alloys are used in the aerospace industry for jet engine components, as well as for rocket and satellite components.
Conclusion
Nickel-based alloys have many beneficial properties that make them ideal for a variety of applications. These alloys are primarily divided into three classes, which are nickel steels, high-nickel alloys, and superalloys. Nickel-based alloys are primarily used in applications requiring high strength and corrosion resistance, such as in fasteners, bolts, pressurized tanks, heat exchangers, and piping systems. Nickel-based alloys are also used in the aerospace industry for jet engine and rocket components.
