Rolled carbon steel coil is an iron-carbon alloy with a carbon content of 0.0218%~2.11%, also known as carbon steel. It also contains small amounts of silicon, manganese, sulfur and phosphorus. In general, the higher the carbon content of carbon steel, the greater the hardness, the higher the strength, but the lower the plasticity. Low carbon steel coil is divided into carbon structural steel, carbon tool steel and free cutting structural steel. Carbon structural steel is divided into engineering construction steel and machine manufacturing structural steel; According to the smelting method, it can be divided into open hearth steel and converter steel; According to deoxidation method, it can be divided into boiling steel (f), killed steel (z), semi killed steel (b) and special killed steel (TZ); (4) According to the carbon content, carbon steel can be divided into low carbon steel (WC ≤ 0.25%), medium carbon steel (WC 0.25% - 0.6%) and high carbon steel (WC > 0.6%).…