Although it is added in small doses of 0.03% up to 3% (Usually between 0.1 -1%) to metals, it is the most influential element in many materials used in machine shops.

Carbon content in carbon steel determines its strength and ductility.

The higher carbon content, the higher steel strength and the lower its ductility.

According to the steels classification there are following groups of carbon steels:

  • Low carbon steels (C < 0.25%)
  • Medium carbon steels (C =0.25% to 0.55%)
  • High carbon steels (C > 0.55%)
  • Tool carbon steels (C>0.8%)

Cast iron

Cast iron is an alloy of iron, carbon and silicon and it is hard and brittle.

Carbon content in CI may be within 1.7% to 3% and carbon may be present as free carbon or iron carbide Fe3C.

In general, the types of cast iron are grey, white and malleable cast iron etc.

Stainless Steel

Most of the stainless steels have carbon in the range of 0.03 to 0.1 percent. Stainless steel with carbon less than 0.035 percent is classified as L grades (low carbon grades) and those with Carbon content more than 0.08 percent are classified as H grades (higher carbon grades).

Cutting Materials


Carbide refers to cutting tools made out of sintered tungsten carbide. It is composed of an equal number of Tungsten and Carbon atoms; thus, the primary cutting material used in machine shops would not exist without carbon.


PCD stands for “Poly Crystalline Diamond,” the hardest available cutting material. PCD is a synthetic diamond produced by sintering diamond particles and a metal binder at a high temperature and pressure.
The diamond is a structure of Carbon atoms; thus, carbon is the primary material in a PCD cutting tool.