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In heavy manufacturing industries, there is always a need to use steel and other kinds of metal for different kinds of productions. Some of these can sometimes include machines working at very high temperatures for which you will need metals that can withstand such temperatures. This is why superalloys were created as normal alloys and pure metals may not be able to do this.
Superalloys or high-performance alloys can operate at a high fraction of their melting point. They optimize their natural strength to achieve high performance. They are also resistant to oxidation and corrosion, have great mechanical strength, good surface stability, and are resistant to thermal creep deformation.
Superalloys find a lot of application in aerospace and marine turbine engines. They come in different categories and are commonly identified by their brand names which are usually the primary elements used in making them. You can read about them here. A popular element is nickel and common superalloys that are nickel-based are Monel, Inconel, and Incoloy.
What is Inconel 718
Inconel 718 is a nickel-based superalloy with high strength and resistance to corrosion, high pressure as well as temperatures of up to around 7000C. It can also be referred to as UNS N07718 or simply alloy 718. It is composed of about 55% nickel and around 17-21% chromium which is the secondary material. Other materials including niobium, tantalum, molybdenum, manganese, aluminum, titanium, silicon, copper, and so on make up around 4.75 – 5.5% of the alloy.
Due to its uniqueness, Inconel 718 is useful in a variety of applications including the manufacture of airplanes and military equipment.
Characteristics of Inconel 718
High Mechanical Strength
At normal temperature, alloy 718 has a minimum of 1035 MPa tensile strength and yield strength of 725 MPa. When it undergoes precipitation or solution, the yield strength increases to 1035 MPa while the tensile strength goes up to 1240 MPa. Tensile and yield strength help show how much stress a piece of metal can withstand before it changes shape permanently or breaks.
Temperature Resistance
UNS N07718 shows an effective resistance to high temperature and heat. It can create a strong and stable oxide layer when it is exposed to heat which protects it from damage. In cryogenic conditions that show how resistant a material is to temperature, it works quite well and has a good rating.
Resistance to Corrosion
The chromium contained in Inconel 718 makes it resistant to water and other elements like acids. Its protective oxide layer prevents any form of oxidation so it does not get corroded.
Good Welding Quality
Inconel 718 was created to address the issue of brittleness and cracking at welding points in other Inconel alloys. The molybdenum present helps in making it more suitable for welding notwithstanding the kind of welding method that is used.
Malleable and Good machining Quality
Alloy 718 is malleable and does not show any signs of strain hardening when a machining or shaping tool is used on it. It is easy to machine even when using a hard cutting implement.
How Inconel 718 is Produced?
This superalloy can be produced by:
Annealing: This is a process of exposing the metal to heat and then gradually lowering the temperature. Metal components are completely dissolved and they precipitate properly, giving the alloy its strength. This enhances its strength and resistance to stress
Precipitation Hardening: This is a method that boosts the strength of the alloy by introducing impurities into it before it is heated. This process can also be called age hardening or precipitation heat treatment. You can read more about it here: https://www.thoughtco.com/precipitation-hardening-2340019.
What are the Applications of Inconel 718?
With its strong properties and characteristics, UNS N07718 is used in various forging applications. It is used to make parts that can come in various shapes and is suitable for use in making aeronautic and automobile parts, jet engines, marine turbines, fuel lines, etc.
Other applications include the following:
- 3D printing
- Die casting
- Gas turbine engines
- High-temperature fasteners
- Motor shafts for electric submersible well pump
- Turbocharger rotors and seals and so on. You can check out this article for more on
Conclusion
Inconel 718 is a great metal to use when you need a material that can withstand a high level of stress and high temperatures. So, if you are a business involved in making machine parts and components, you should contact experts that can help you forge these parts with this superalloy and you can be sure that you are getting the good stuff.