Carbon steel

Carbon steel, or carbon steel is a special grade of steel with some very special steel properties. What distinguishes carbon steel, where it is used, and what special steels there are in this group, you can read in detail in this post.


Carbon or carbon steel is a colloquial name. It is misleading insofar as every steel contains carbon as the most important element besides iron. This first makes the steel steel and distinguishes it from iron. Correctly, carbon steels are called AHS steels. The abbreviation AHSS stands for (Advanced High Strength Steel).

Grouping of AHS steel (AHSS)

AHSS belong to the unalloyed steels. In this group they are high strength steels, with even higher strength than so-called high speed steels which are also used for other purposes (as tool steels for high speed machines). AHSS and HS steels therefore have completely different fields of application. Only the higher strength than ordinary steels makes them related to each other.

But AHSS is just an umbrella term. These steels include many important and commonly used steel groups:

  • Multiphase steels
  • Dual phase steels (predominantly ferritic microstructure, but with embedded martensite islands)
  • Complex Phase steels
  • so-called bake-hardening steels (steels which harden when heated)

TRIP and TWIP steels are generally also counted as carbon steels. Typical of these steels is that they become harder when deformed.

Application of carbon steels

An important application for these steels is the automotive industry. Important steel grades are especially the bake hardening steels (as they are automatically hardened in a baked enamel finish) and also the TRIP and TWIP steels.

TWIP steels are mainly used in the crumple zone. If you get deformed, harden yourself. TRIP steels are appreciated in the automotive industry because of their good ductility and high strength compared to other steels, which makes a lighter construction possible

Tips & Tricks

Anyone who would like to do it himself to forge a knife blade, which is a beginner with carbon steel (in the trade often simply referred to as C-steel) very well advised. In a sense, it is regarded as a classic for blacksmith beginners, with whom one can produce very high-quality and robust blades. He is quite an excellent knife steel. Carbon steel is not stainless, however. Therefore, you have to make sure that the blade is always kept dry and well maintained.

Video Board: High Carbon Steel vs Mild Steel Test