Ordinary carbon structural steel

 Ordinary carbon structural steel

　　Ordinary carbon structural steel, also known as ordinary carbon steel, has wide restrictions on carbon content, performance range, and content of phosphorus, sulfur and other residual elements. In China and some countries, it is divided into three categories according to the guarantee conditions of delivery: Class A steel (Class A steel) is the steel with guaranteed mechanical properties. Class B steel (Class B steel) is steel with a guaranteed chemical composition. Special steel (C-type steel) is a steel that guarantees both mechanical properties and chemical composition, and is often used to manufacture more important structural parts. China currently produces and uses the most A3 steel (Class A No. 3 steel) with a carbon content of about 0.20%, which is mainly used for engineering structures.

　　Some carbon structural steels also add trace amounts of aluminum or niobium (or other carbide-forming elements) to form nitrides or carbide particles to limit grain growth, strengthen the steel, and save steel. In China and some countries, in order to meet the special requirements of professional steel, the chemical composition and properties of ordinary carbon structural steel have been adjusted, thus developing a series of professional steel of ordinary carbon structural steel (such as bridges, buildings, Steel bars, steel for pressure vessels, etc.).