Overview
Stellite alloy is a commonly used superalloy. It plays an irreplaceable role in many fields, especially in the aerospace field. Stellite alloy is known for its excellent high-temperature wear resistance. At the same time, it can be processed into products of various shapes.
In this article, we will introduce Stellite alloy in detail based on its chemical composition and mechanical properties.
What is 
Stellite Alloy?
Stellite alloy is a general term for a series of cobalt-chromium alloys. It is a corrosion-resistant and wear-resistant superalloy.
Stellite alloy is a cobalt-based superalloy with cobalt as the main element. Cobalt brings good high-temperature resistance to the alloy. At the same time, due to the special crystal structure of cobalt, it also helps the wear resistance of the alloy.
Chromium is also an important element in Stellite alloy. It can form a protective film on the surface of the alloy to prevent corrosion of the alloy. It is the most important corrosion-resistant element in Stellite alloy.
Carbon is the most important element to improve the wear resistance of Stellite alloy. Carbon in the alloy synthesizes carbides with other elements. These carbides will be dispersed in the alloy, so that the internal structure of the alloy remains stable, thereby improving the strength and wear resistance of the alloy. However, during production, attention should be paid to controlling the particle size of the carbide. The smaller the particle size, the better the wear resistance of the alloy.
Stellite alloy can be produced by deformation, casting and powder metallurgy. Among them, powder metallurgy is the most widely used production method. This process can obtain very fine carbide particle size.
Composition and Properties of Stellite Alloy
Stellite alloy has a variety of different grades. Different grades have different chemical compositions. The following are the common Stellite alloy grades:
Below, let's introduce the key elements that determine the Stellite alloy grades one by one:
Cobalt and Chromium
Cobalt and chromium are the sources of Stellite alloy's high temperature resistance and corrosion resistance. These two properties are very important for alloys. Therefore, their composition in Stellite alloy does not change much.
Carbon and Tungsten
Carbon and tungsten are elements that determine the wear resistance of alloys. Wear resistance is generally positively correlated with the strength of the alloy. However, carbon mainly improves the strength of the alloy by dispersion distribution, while tungsten improves the strength of the alloy more by solid solution strengthening. Therefore, their roles cannot replace each other.
In addition, higher strength often means lower plasticity. Therefore, different Stellite alloys will vary in carbon content and tungsten content to meet different plasticity requirements.
The carbon and tungsten contents of Stellite 6, Stellite 12, Stellite 3, and Stellite 20 are listed below:
You can see that their carbon and tungsten contents increase in turn, so their strength and wear resistance also increase in turn, and their plasticity decreases in turn.
Molybdenum
Molybdenum is also a good solid solution strengthening element, which can also improve the strength of the alloy. At the same time, molybdenum can also improve the corrosion resistance of the alloy. Stellite 21 is a typical Stellite alloy containing molybdenum.
Nickel
Nickel is the main element in nickel-based superalloys, thanks to its excellent high-temperature resistance. But in Stellite alloy, cobalt replaces the role of nickel. However, if you want to further increase the high-temperature resistance of the alloy, you can also add a certain amount of nickel to the Stellite alloy. Stellite 31 does this.
Silicon and Manganese
Silicon and manganese are often considered as impurity elements in Stellite alloys. They will reduce the casting properties of the alloy. Therefore, if the Stellite alloy is produced by casting, you need to strictly control the content of silicon and manganese.
FAQ
What are the most commonly used Stellite alloys?
Stellite 6, Stellite 6B, Stellite 12, Stellite 3, and Stellite 20 are the most commonly used Stellite alloys. They meet most of the requirements for wear resistance and corrosion resistance. Among these alloys, Stellite 6 is the most used alloy.
What is the price of Stellite alloy?
Unlike other superalloys, the price of Stellite alloy does not vary much due to the grade. However, its price is greatly affected by different products. At the same time, the fluctuation of cobalt prices also has a great impact on the price of Stellite alloy. Therefore, if you need a certain price, please contact us and tell us your specific needs, and we will give you the most professional quotation.
What is the difference between Stellite alloy and other superalloys?
From the perspective of composition, most superalloys are nickel-based superalloys, while Stellite alloy is cobalt-based superalloy. From the perspective of performance, other superalloys focus on high-temperature corrosion resistance, while Stellite focuses more on high-temperature wear resistance.
Further Reading
Conclusion
Stellite alloy is a general term for a series of cobalt-chromium alloys. Cobalt brings high temperature resistance while chromium brings corrosion resistance. At the same time, carbon and tungsten are important sources of wear resistance in Stellite alloy. Different carbon and tungsten contents determine the wear resistance of Stellite alloy.
We produce a variety of different Stellite alloys, please do not hesitate to contact us for any needs.
