Billet is a primary product obtained by casting molten steel produced in a steelmaking furnace, typically in the form of slabs (for sheet products), blooms (for section and wire products), or tube blanks. It is an important semi-finished product in the steel industry, possessing good plasticity and machinability. Billets serve as raw materials for downstream processes and can be transformed through rolling, forging, drawing, and other processing methods into finished steel products of various specifications and shapes, such as steel plates, steel tubes, and steel bars. Billets are widely used in construction, machinery manufacturing, shipbuilding, automotive manufacturing, and other fields for producing various components and structural materials. Carbon steel, also known as plain-carbon steel, has a carbon content of approximately 0. 0.02%-2%. Carbon steel is divided into high-carbon steel, medium-carbon steel, and low-carbon steel. The higher the carbon content, the higher the hardness, strength, and wear resistance of the steel after heat treatment, but it also becomes more brittle. The lower the carbon content, the softer and more ductile the steel.