Carbon steel refers to steel with carbon content between 0.05 and 2.1%. The American Institute of Iron and Steel (AISI) defines carbon steel as: no minimum amount of chromium, cobalt, molybdenum, nickel, niobium, titanium, tungsten, vanadium, zirconium or any other element is specified or required to achieve desired alloying; The minimum value of copper shall not exceed 0.40%; Or the maximum content of any of the following elements not exceeding the stated percentage: Manganese 1.65%; Silicon (0.60%); The term carbon steel can also be used to refer to steel other than stainless steel; In this use, carbon steel may include alloy steel. High carbon steel has many different uses, such as milling machines, cutting tools (such as chisels) and high strength wires.
These applications require finer microstructure, which improves toughness. Carbon steel is a popular metal choice for cutting tools because it contains a lot of carbon, which makes the edge of the blade hold stronger.
In order to make full use of this kind of steel, proper heat treatment is very important. Otherwise, the knife may become brittle or too soft to hold the blade. With the increase of carbon content, steel has the ability of hardening and strengthening during heat treatment. However, it becomes less malleable. Regardless of heat treatment, higher carbon content will reduce weldability. In carbon steel, the higher carbon content reduces the melting point.