CNC Machining Stellite: The Complete Guide

The process of CNC machining stellite consists of using CNC machines to shape or fabricate the components that are made using stellite. Stellite is an alloy of cobalt and chromium which offers seamless corrosion and wear resistance.

This guide below provides you with a detailed analysis of the CNC machining stellite, its different grades, applications, and essential tips. So, let's read below.

 What is a CNC Machining Stellite?

Stellite is an alloy of cobalt and chromium and also comprises some other elements like nickel, carbon, and tungsten to enhance its properties. Stellite is known for its excellent resistance against abrasion and wear and also offers high hardness.

Stellite proves to be a suitable material in environments where corrosive conditions prevail and it even maintains its mechanical properties at high temperatures. CNC machining helps to achieve the required shape and precision for the stellite components and it even helps with creating components that have complex geometries and tight tolerance.

CNC Machining Stellite Process

CNC machining Stellite comprises different processes and these comprise the following:

CNC Turning

CNC turning consists of rotating the workpiece of stellite on a non-rotating tool that moves in a linear form to cut the material and give the Stellite component the desired shape. The process of CNC turning uses carbide tips which can handle the hardness of the Stellite material and the heat generated during the process. During CNC turning it is suggested to keep the speed of the cutting tool slow and use a coolant for managing the heat.

 CNC Milling

CNC milling consists of a rotating cutting tool that helps to remove material from the stationary workpiece. It is suitable for manufacturing Stellite components that have complex shapes and need detailing in features. In order to manage tool wear the speed of the milling machine must be slow; it even helps dissipate heat.

CNC Drilling

CNC drilling helps in creating cylindrical holes in stellite with the help of rotating cutting tools. The process of CNC drilling uses solid carbide-made drills consisting of sharp edges. The process of CNC drilling helps create deep holes in stellite components.

Different Grades of Stellite

Stellite machined parts can be manufactured from the different grades of stellite and each grade has its distinctive properties making it suitable for versatile applications. Some of these grades of stellite are as follows

Stellite 1

Stellite 1 comprises a high composition of chromium and cobalt which makes it exceptionally hard and equipped with wear resistance. Due to its high hardness, it is commonly used in applications that require components capable of withstanding severe erosion and abrasion. It is usually used for manufacturing cutting tools, valve components, or other wear-resistant parts.

Stellite 6

Stellite 6 is one of the most commonly used grades of Stellite due to its excellent resistance against wear and corrosion resistance. It has a major composition of chromium and cobalt but at the same time comprises a significant amount of carbon and tungsten. Hence, it is suitable for applications that need high corrosion resistance like bearings, valve seats, etc.

Stellite 12

Stellite 12 is rich in carbon which increases its hardness and applications that need cutting resistance may use this grade. It has a brittle structure and can perform well in high-temperature environments with durability. It is commonly used for manufacturing pump components and cutting tools.

Stellite 21

Stellite 21 consists of nickel and molybdenum in its composition which offers it the highest corrosion resistance. It is hard and less brittle compared to other grades but offers seamless wear resistance. It can be used in chemical and medical industries and helps in manufacturing medical implants, surgical instruments, etc through CNC machines.

Stellite 31

Stellite 31 is resistant to high temperatures consisting of a high amount of tungsten. It is suitable for power generation and aerospace applications due to its capability to withstand extreme temperatures. It is commonly used in engine components, turbine blades, etc.

Advantages of Stellite in CNC Machining

The stellite CNC machined parts offer various benefits and some of these are as follows:

Wear Resistance

Stellite is known for its exceptional wear resistance which makes it suitable for components that are subjected to high levels of erosion and abrasion. The components made using Stellite have the capability to maintain their functionality and integrity in harsh conditions in the long run.

Corrosion Resistance

Stellite alloys are highly resistant against corrosion, hence the components made using the Stellite material may be exposed to corrosive substances like saltwater or chemicals without any chance of corroding. Hence they are suitable for industries like oil and gas, marine and chemical processing where the components are subjected to corrosive agents.

Extreme Temperature Functionality

The Stellite in CNC machining retains its properties even when subjected to extreme temperatures. The alloys of Stellite do not lose their hardness and strength when exposed to high temperatures. Therefore they are suitable for multiple applications like the power generation sector, aerospace, automobile, and many more.

Strength

Stellite is known for its robust strength which adds durability to the life of the components made using it. Hence, they do not deform easily and also maintain their shape when subjected to high mechanical stress. Therefore they can perform very well in applications where other materials end up with deformation.

Challenges for Custom Stellite Machined Parts

Although Stellite CNC machined components are highly advantageous, there are certain challenges which are given below:

High Tool Wear

One of the major challenges faced in CNC machining stellite is that it has a high hardness and abrasive properties due to which significant tool wear is caused. Although the hardness of Stellite makes it durable for components, while machining, the tools used may wear out quickly making the machining process complex and costly.

Management of Heat

Stellite is equipped with low thermal conductivity which means the heat dissipation is not very good during the process of machining. When heat builds up the material may face thermal damage and the need to ensure the heat management strategies is important, it helps in increasing the tool's life.

High Cost

Stellite is expensive when compared to other materials, it is because cobalt and the other materials used in its composition are expensive. The cost of Stellite increases the cost of the components.

Tips to Stellite CNC Machining

Stellite machined parts can be achieved perfectly by following some important tips as given below:

1. To achieve an effective stellite custom part, it is important to use high-quality cutting tools. The tools made from carbide are capable of withstanding the hardness of stellite and it even helps in reducing the tool wear.
2. Cutting parameters require careful optimization when machining stellite, the speed and feed rates must either be slow or moderate so that tool wear and heat generation is minimized.
3. It is vital to apply the right coolant during the process of machining, it helps to reduce thermal stress and also improves the life of the tools.
4. Advanced toolpath strategies like highly efficient milling and peck drilling help in enhancing the Stellite machining process. It helps to reduce tool wear, distributes heat evenly, and even improves chip evacuation.
5. CNC machining setup is required to be stable and rigid so that during the machining process, vibrations are minimized.
6. Keep an eye on the tool wear and replace them when needed so that the quality of the stellite component is maintained with accurate dimension and precision.
7. In order to achieve the required surface finish, the stellite parts may need additional processes which may consist of polishing, coating, and grinding which helps to extend the life of components and enhance their appearance.
8. Machining stellite requires skilled operators who understand the challenges associated with the material and its properties so that the best outcome is achieved.

Surface Finishes for Stellite Machined Parts

Stellite machined parts may require additional surface finishing, some of these surface finishing options are as follows:

Grinding

Stellite machined parts need an added process of grinding which helps to achieve a high precision and smooth surface of the stellite machined components. The process of grinding uses an abrasive wheel or a belt which helps in removing the material in small amounts. It helps to add tight tolerance and refined surface to the components.

Polishing

Polishing enhances the surface of the Stellite components and even reduces friction. The process uses polishing components to enhance the surface and make them shine like a mirror. The process of polishing even helps in removing any irregularities in the surface.

Coating

Coating consists of applying a protective layer on the CNC machined Stellite components which improves their corrosion and wear resistance and also adds durability. These coatings consist of hard coatings, thermal sprays, and electroplated coats which are selected based on the application. requirements of the custom Stellite parts.

Applications of Stellite CNC Machining

Stellite has certain properties that make it suitable for different applications and some of these are given below:

Aerospace

In the aerospace industry, stellite CNC machining helps manufacturing components that need stable performance under high pressure and temperature and durability. Turbine, nozzle components, blades, and engine parts are usually made from CNC machined stellite. Stellite helps these materials to maintain their structural integrity even when subjected to extreme thermal and mechanical stress.

Medical

In the medical industry, stellite CNC machined components are used for surgical instruments, dental tools, and implants. The stellite components offer resistance to corrosion and biocompatibility which makes them safe for use in the longer run. Also, due to their corrosion resistance property, they even are suitable for being exposed to the sterilization process.

Oil and Gas

In the oil and gas industry, stellite CNC machining helps in manufacturing components like pump parts, drill bits, and valve seats which operate under corrosive environments. Due to the excellent corrosion resistance, the stellite parts may withstand in the longer run with efficiency.

Power Generation

In the power generation industry, the stellite is used in various ways like in heat exchangers, turbine blades, and combustion chamber parts. These components are subjected to high temperature during their operations and hence the ability of Stellite to maintain its hardness makes the stellite components suit these applications.

Conclusion

The guide above has offered a detailed insight into stellite CNC machining and how the stellite machined components can be used in various industries with different grades. Stellite is a versatile material that comprises multiple properties, when you need to have custom Stellite components learning about it is equally crucial.

CNC Machining Stellite Service at DEK

DEK is one of the leading manufacturers of custom stellite machined parts for different applications. You can get assistance on what are the suitable stellite grades for your components and also we offer you highly precise and accurate stellite custom machined parts that offer durability and affordability.

FAQs

Which Type of Stellite is the Most Widely Used?

Stellite 6 is the most popular alloy of Stellite used, it offers wear resistance and has an all-around performance in multiple industries due to its excellent mechanical and chemical resistance.

Is Stellite Hard to Machine?

Stellite is hard to machine as it has a high content of chromium and cobalt which makes them have high melting points.

Is Stellite Better than 316 Stainless Steel?

Stellite is far much better than 316 stainless steel when assessed in terms of corrosion and wear resistance, especially when subjected to harsh environments and high temperatures. However, stainless steel is easy to machine and offers cost-effectiveness.