The raw material of carbon steel pipe is round tube blank, which needs to be cut and processed by a cutting machine to form a billet with a length of about 1 meter, and then sent to the furnace for heating through a conveyor belt. The billet is fed into the furnace for heating, with a temperature of approximately 1200 degrees Celsius. The fuel is hydrogen or acetylene. Temperature control in the furnace is a crucial issue. After the round tube billet is discharged from the furnace, it needs to be pierced through by a pressure piercing machine. The commonly used piercing machine is a conical roller piercing machine, which has high production efficiency, good product quality, large perforation and expansion capacity, and can pierce various steel grades. After perforation, the round tube blank is sequentially rolled, continuously rolled, or extruded by three rollers. After squeezing, the pipe needs to be detached and sized. The sizing machine uses a conical drill bit to rotate at high speed into the steel billet for drilling, forming a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine drill bit. After the steel pipe is sized, it enters the cooling tower and is cooled by water spray. After cooling, the steel pipe needs to be straightened. After straightening, the steel pipe is transported by a conveyor belt to a metal inspection machine (or hydraulic test) for internal inspection. If there are cracks, bubbles, and other issues inside the steel pipe, they will be detected. After the quality inspection of steel pipes, strict manual selection is also required. After the quality inspection of the steel pipe, the number, specification, production batch number, etc. are sprayed with paint. And lifted into the warehouse by a crane.