Steel vs Iron in CNC Machining: Understanding the Differences(cnc fixtures Antony)

  • Time:
  • Click:4
  • source:WEINBERG CNC Machining


CNC machining is a highly versatile and precise manufacturing process that utilizes computer-controlled machines to produce intricate parts and components. The choice of material plays a crucial role in determining the quality, strength, and functionality of the final product. Among the popular materials used in CNC machining, steel and iron stand out due to their exceptional properties. This article will explore the differences between steel and iron in the context of CNC machining, shedding light on their production processes and highlighting their unique characteristics.

Steel Production for CNC Machining:

Steel is an alloy composed primarily of iron and carbon, along with other elements such as manganese, chromium, and nickel. This combination imparts desirable qualities essential for CNC machine parts, such as excellent strength, durability, and corrosion resistance. Producing steel involves multiple steps, including mining raw materials, refining, smelting, and further processing.

1. Extraction: Iron ore, the primary raw material for steel production, is extracted from mines through drilling and blasting. Once mined, it undergoes beneficiation, where impurities are removed to improve its purity.

2. Smelting: The purified iron ore is mixed with coke (carbon) and limestone in a blast furnace, forming molten pig iron. Pig iron contains about 3-5% carbon and high amounts of silicon, making it brittle and unsuitable for most applications.

3. Steelmaking: To convert pig iron into steel suitable for CNC machining, it undergoes another refining process called steelmaking. Various methods like basic oxygen, electric arc, or open hearth furnaces are employed to remove excess carbon and impurities while adding specific alloying elements to enhance its desired properties.

4. Casting and Forming: The molten steel is then cast into various forms, such as slabs, billets, or ingots, which can be further shaped using rolling mills, extrusion processes, or forging techniques to obtain the desired dimensions and properties.

Iron Production for CNC Machining:

While iron is one of the primary constituents of steel, it also possesses distinctive qualities that make it a preferred material for specific CNC machining applications. Cast iron, in particular, exhibits excellent wear resistance and thermal stability, making it suitable for parts requiring high strength and vibration damping characteristics. The production process of iron primarily involves refining pig iron obtained during the steelmaking process.

1. Refinement: Pig iron is melted down again and subjected to further refining by removing impurities such as sulfur and phosphorus. This refinement process enhances the mechanical properties of the iron, making it more suitable for various CNC machining purposes.

2. Casting: The refined molten iron is cast into molds, where it solidifies and takes the desired shape. Different casting methods like sand casting or investment casting are employed based on the complexity and precision requirements of the final product.

Steel vs Iron in CNC Machining:

Both steel and iron have their unique advantages and considerations when it comes to CNC machining applications.

1. Strength and Durability: Steel offers exceptional tensile strength, hardness, and impact resistance, making it ideal for robust components exposed to heavy loads and dynamic forces. On the other hand, iron provides superior wear resistance and vibration damping properties, which are vital for machine tool beds, engine blocks, and gears.

2. Corrosion Resistance: Stainless steels, thanks to their chromium content, provide excellent corrosion resistance, making them suitable for parts used in harsh environments, such as marine applications. However, iron is prone to rusting due to its reactive nature, necessitating proper surface treatments or coatings to prevent oxidization.

3. Machinability: Steel, with its consistent microstructure and controllable grain size, offers excellent machinability, reducing tool wear and ensuring dimensional accuracy. Conversely, cast iron can present challenges due to its abrasive tendencies and graphite flakes, requiring specialized cutting tools and techniques for optimal machining performance.


Understanding the differences between steel and iron in CNC machining is crucial in choosing the most suitable material for specific applications. While both materials have their unique properties and production processes, steel offers exceptional strength, corrosion resistance, and machinability, making it an excellent choice for various parts. On the other hand, iron provides unmatched wear resistance and thermal stability, making it ideal for applications that demand high strength and vibration damping characteristics. By considering these factors, manufacturers can make informed decisions to produce durable, precise, and reliable CNC machine components. CNC Milling