Ordinary carbon steel is also known as ordinary carbon structural steel, also known as ordinary carbon steel. The carbon content is 0.06-0.22%, and less than 0.25% is commonly used. Belonging to low carbon steel, each metal grade represents the low yield point of the steel when the thickness is less than 16mm. Compared with high-quality carbon steel, there are wider restrictions on carbon content, property range and content of phosphorus, sulfur and other residual elements. According to the guarantee conditions of delivery, my country and some countries divide ordinary carbon steel into three categories: Class A steel (Class A steel), which only guarantees mechanical properties and does not guarantee chemical composition, Class B steel (Class B steel), Only the chemical composition is guaranteed, but the mechanical properties are not guaranteed; the special steel (C-type steel) guarantees both the chemical composition and the mechanical properties. Special steel is often used to manufacture more important structural parts.

Plain carbon steel can be smelted by oxygen converter, open hearth or electric furnace, and is generally hot rolled into steel plates, strips, profiles and bars. Steel sheets are generally delivered in hot rolled (including controlled rolling) or normalized state. The chemical composition, tensile properties, impact energy and cold bending properties of the steel shall comply with relevant regulations.