CNC Machining: Understanding the Difference Between Cast Iron and Steel(how much is brass per pound worth Rita)

  • Time:
  • Click:5
  • source:WEINBERG CNC Machining


When it comes to manufacturing, understanding the properties of different materials is crucial. In this article, we will delve into the realm of CNC machining and explore the differences between two commonly used materials – cast iron and steel. By comprehending their distinct characteristics, you can make informed decisions in choosing the right material for your manufacturing needs.

Cast Iron:

1. Composition and Properties:
Cast iron is primarily composed of iron with a carbon content ranging from 2% to 4%. Its unique properties, such as high heat resistance and excellent wear resistance, make it an ideal choice for numerous applications. Moreover, the graphite flakes present in cast iron offer good vibration damping capabilities.

2. Types of Cast Iron:
a) Gray Cast Iron: This type of cast iron is renowned for its easy machinability. It exhibits low melting temperature, excellent thermal conductivity, and exceptional dampening capacity. However, gray cast iron has relatively low tensile strength compared to other materials.

b) White Cast Iron: With higher carbon content than gray cast iron, white cast iron demonstrates increased hardness and abrasion resistance. Consequently, it is extensively used in cutting tools, grinding balls, and cemented carbides.

c) Ductile Cast Iron: Known for its notable toughness and ductility, this material offers enhanced mechanical properties when compared to other types of cast iron. Also, its improved corrosion resistance makes it suitable for applications requiring long-term durability.


1. Composition and Properties:
Steel consists predominantly of iron alloyed with carbon, typically varying from 0.05% to 2%. Unlike cast iron, steel possesses lower carbon content which contributes to its remarkable strength and versatility. Additionally, various alloying elements such as chromium, nickel, and manganese are incorporated to further enhance specific properties.

2. Types of Steel:
a) Carbon Steels: These steels primarily consist of iron and carbon, making them cost-effective and widely used. Carbon steels possess good formability, high strength, and excellent machinability. However, their relatively low resistance to corrosion necessitates additional measures for rust prevention.

b) Stainless Steels: Due to the inclusion of chromium (10% or more), stainless steels exhibit a high degree of corrosion resistance. This property, combined with excellent durability and aesthetic appeal, make stainless steel ideal for applications in various industries such as food processing, architecture, and medical equipment.

c) Tool Steels: Tool steels are designed specifically for cutting, drilling, and shaping other materials. These steels incorporate extra elements such as tungsten, molybdenum, and cobalt to enhance hardness, wear resistance, and heat resistance.

CNC Machining and Material Selection:

When it comes to CNC machining, careful material selection plays a pivotal role in achieving desired outcomes. The choice between cast iron and steel depends on several factors including the specific application, required mechanical properties, and budget constraints. Here are some crucial considerations:

1. Strength and Durability:
If your application demands high strength and resilience against external forces, steel is an excellent choice due to its superior tensile strength. On the other hand, if damping capacity and thermal conductivity are essential, cast iron's inherent properties make it well-suited for vibration reduction and heat dissipation purposes.

2. Machinability:
Both cast iron and steel can be effectively machined using CNC techniques. However, gray cast iron exhibits exceptional machinability due to its graphite content. It readily breaks apart during machining, resulting in shorter cycle times and decreased tool wear. Steel can also be machined efficiently but may require specialized tools and techniques depending on its alloying elements.

3. Cost:
In terms of cost-effectiveness, cast iron generally tends to be cheaper than most types of steel due to lower material costs and simpler production processes. However, certain factors such as the required properties, tolerances, and complexity of the final product can influence overall manufacturing costs significantly.


In summary, understanding the difference between cast iron and steel is essential for successful CNC machining operations. While both materials have distinct advantages and disadvantages, their suitability for various applications can be attributed to specific characteristics such as strength, machinability, thermal conductivity, and cost. By considering these factors wisely, manufacturers can optimize their production processes and achieve superior results in terms of performance, durability, and efficiency. CNC Milling