As the name suggests, carbon steel is steel that contains carbon. However, not all steel qualifies as carbon steel. Technically, carbon steel is an alloy composed primarily of iron and carbon, with small amounts of other elements such as silicon, manganese, sulfur, and phosphorus. Although these additional elements are present in minor quantities, they can still influence the steel’s overall properties. The carbon content in carbon steel typically ranges from 0.0218% to 2.11%. Below this range, the material is classified as industrial pure iron; above it, it becomes cast iron—both of which differ significantly from carbon steel in terms of physical characteristics and applications.

The properties of carbon steel largely depend on its carbon content. In general, the higher the carbon content, the greater the strength and hardness. However, this increase in strength usually comes at the cost of reduced ductility and toughness. In other words, high-carbon steel is harder and more wear-resistant but also more brittle and less capable of handling deformation or tensile stress. On the other hand, steel with lower carbon content tends to be softer, more ductile, and easier to process or weld, though it may lack the strength required for high-stress applications.

Carbon steel is typically divided into three categories based on its carbon content: low carbon steel, medium carbon steel, and high carbon steel.

Low carbon steel (approx. 0.02%–0.25% carbon): Soft and highly ductile, it offers excellent weldability and cold workability. It's commonly used in construction materials, sheet metal, screws, and piping.

Medium carbon steel (approx. 0.25%–0.6% carbon): Balances strength and toughness, making it suitable for structural components like machine shafts, gears, and chains. It’s a popular choice in engineering applications.

High carbon steel (approx. 0.6%–2.11% carbon): Extremely hard and wear-resistant but less ductile and more challenging to process. It’s often used to make tools, sprin