CNC Milling and Machining Ferrous and Nonferrous Metals

Computer numerical control (CNC) machining is a manufacturing process that uses preprogrammed software in computers to guide the movement of CNC machinery. With this method, different products are produced for a variety of industries.

There are many different materials used in CNC machines, including a range of metals. These can be divided into two categories—ferrous and nonferrous. While ferrous metals contain iron (from Latin: ferrum), nonferrous metals do not.

Keep reading to find out more! In our guide, we’ll explain more about the differences between ferrous vs. nonferrous metals and how they’re used in CNC machining.

What Are Ferrous Metals?

Metals categorized as ferrous contain a large amount of iron. However, metals that contain only trace amounts of iron are not classified as ferrous. Some of the main types of ferrous metals include:

• Stainless steel: Stainless steel can resist corrosion better than other ferrous metals, thanks to high levels of chromium. There are many different subgroups of stainless steel, which are used in a range of applications, including appliances and food-grade equipment.
• Alloy steel: These types of metals are formulated for specific purposes. A range of elements from copper to tungsten might be used with alloy steel to tailor them to fit a certain application. Alloys are often used in tools and machining equipment.
• Cast iron: There is a higher amount of carbon in cast iron than most other ferrous metals, which gives it a lot of strength despite being relatively brittle. You’ll see cast iron used for things like cookware or small components, like gears.
• Carbon steel: One of the most common types of ferrous metals, carbon steel has a chemical composition of over 90% iron. Carbon steels are often used in automotive components, as well as for furniture and other structures.

Advantages of ferrous metals

• High strength: One of the primary advantages of ferrous metals is their high tensile strength, making them ideal for use in construction and industrial machinery. This strength supports heavy loads and withstands stress without breaking.
• Cost-effectiveness: Compared to many nonferrous metals, ferrous metals are usually more cost-effective. Their abundance and recyclability make them an economical choice for large-scale projects and applications.
• Magnetic properties: Ferrous metals possess magnetic properties, which makes them indispensable in the creation of motors, generators and various electrical appliances. This unique characteristic expands their usability beyond structural applications.

Read: What Is Geometric Dimensioning & Tolerancing (GD&T)

What Are Nonferrous Metals?

What is nonferrous metal? Nonferrous metals contain only trace amounts of iron or none at all. Many nonferrous metals are used in manufacturing, and common ones include:

• Nickel: Nickel is a nonferrous metal known for its durability and the ability to perform in a range of temperature environments. Nickel is often alloyed with other elements and not used in its pure form. Applications include hot-section aerospace equipment and tank production.
• Copper: Copper is needed to create electrical components like wire and terminals, pipes and currency coatings. When tin is alloyed with copper, it’s known as bronze. When alloyed with zinc, you get brass.
• Aluminum: As a widely used type of nonferrous metal, aluminum is often found in aerospace equipment, beams and rails in construction applications and cookware. The composition can change as alloying elements are added to make it pliable and stronger, and it’s lighter than steel.

Advantages of nonferrous metals

• Rust and corrosion resistant: One of the main benefits of using nonferrous metals is that they are rust and corrosion resistant. This helps them last longer and gives them the ability to be used in products that are exposed to the elements.
• Lightweight: Being able to use metals that are lightweight gives them the ability to be used in a range of applications and to be put into different positions that won’t compromise the integrity of a structure.
• Malleable: An added benefit of nonferrous metals is their ability to be molded and shaped. They can be machined, welded, cast and forged into different shapes to suit a variety of purposes much easier than ferrous metals.

Read: CNC Machining Tolerances: Standard Tolerances Explained

Ferrous vs. Nonferrous Metals

When comparing ferrous to nonferrous metals, the primary distinction lies in their iron content. Ferrous metals are rich in iron while nonferrous metals have minimal to no iron content. This fundamental difference contributes to each metal's unique properties and applications.

Ferrous metals, known for their strength and magnetic qualities, are often used in construction and industrial machinery due to their high tensile strength and cost-effectiveness. On the other hand, nonferrous metals are prized for their resistance to rust and corrosion, lightweight nature and malleability—making them ideal for applications ranging from electrical wiring and aerospace components to cookware and decorative items.

Understanding these differences is crucial for selecting the appropriate metal type based on the requirements of a project, whether it demands the durability and magnetic properties of ferrous metals or the lightweight and corrosion-resistant characteristics of nonferrous metals.

Read: CNC vs. Manual Machining: Which is Better?

Machining Ferrous vs. Nonferrous Metals

Machining ferrous and nonferrous metals comes with different sets of challenges and requirements due to the inherent differences in their properties.

Ferrous metals, including various forms of steel and cast iron, present unique challenges:

• They tend to be harder, requiring more aggressive machining techniques.
• High strength and durability make them resistant to wear.
• They are more challenging to cut or shape without the right tools.
• Preferred tools include high-speed steel or carbide tools.

Nonferrous metals, like aluminum, copper and brass, have different properties:

• They are generally softer and more malleable than ferrous metals.
• They are easier to machine, allowing higher machining speeds without the same level of wear on tools.
• Issues such as burring or deformation can arise if not handled properly.
• They require special care and appropriate cutting tools to maintain the integrity of the finished product.

These characteristics emphasize the importance of a deep understanding of both the physical and chemical properties of each metal type. Such knowledge is crucial not only for planning and executing operations but also for ensuring the efficiency and quality of the final product.

Read: What Is CNC Milling? An Introduction

FAQs

1. What is the difference between ferrous and nonferrous metals?

Ferrous metals contain iron, making them magnetic and prone to corrosion due to rust formation. Nonferrous metals, on the other hand, do not contain iron, are not magnetic and are more resistant to corrosion, making them ideal for applications where longevity and material integrity are crucial.

2. What are some examples of ferrous metals?

Ferrous metals are largely made up of iron. Some common ferrous metals include:

• Steel
• Cast iron
• Wrought iron
• Carbon steel
• Alloy steel

3. What are some examples of nonferrous metals?

Nonferrous metals do not contain iron or contain small amounts of it. Examples of nonferrous metals include:

• Aluminum
• Copper
• Lead
• Zinc
• Titanium

4. What are the advantages of milling nonferrous materials?

Milling nonferrous materials, such as aluminum and brass, cuts faster. This can increase productivity and minimize wear on cutting tools, extending their lifespan and reducing the cost of replacements.

5. How can you tell if a metal is ferrous or not?

To determine if a metal is ferrous, check its magnetic properties. Ferrous metals, which contain iron, are typically magnetic, allowing them to be easily identified with a simple magnet test. Additionally, they are prone to rust when exposed to moisture, unlike many nonferrous metals.

Read: CNC Machining FAQs

Learn More About Ferrous vs. Nonferrous Metals With CNC Training at NASCAR Tech in Mooresville, NC!

The CNC Machining Technology program offered at UTI’s NASCAR Technical Institute campus in Mooresville, North Carolina, can help expand your knowledge of the different materials used in the manufacturing industry.^2,85

Specifically, the Mathematics, Materials, and Maintenance course teaches students about the different compositions of ferrous vs. non-ferrous metals. They are taught heat-treatment methods, hardness-testing methods and how to use measurement scales.

This knowledge, along with everything else covered in the 36-week program, can help give students the knowledge they need to pursue an entry-level job as a CNC machinist after graduation.

Eager to start training? Fill out an application to get started. If you want more information before making a decision, request info on our site or contact an Admissions Representative at 1-800-834-7308!