The raw material of the tubi in acciaio al carbonio is the round pipe blank. The round pipe embryo is cut by the cutting machine and processed into the billet with the length of about 1 meter, and sent to the furnace to be heated by the conveyer belt. The billet is fed into a furnace and heated at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is a key issue. After the round tube billet to go through the pressure piercing machine to wear empty. Generally more common punching machine is conical roller punching machine, this punching machine production efficiency, product quality, perforation expansion diameter large, can wear a variety of steel. Perforation, the round tube blank has been three-roll cross-rolling, rolling or extrusion. Squeeze after the tube diameter. Sizing machine through the high-speed rotation of the cone drill bit into the steel embryo drilling, the formation of steel. The inner diameter of the pipe is determined by the outside diameter of the sizing bit. After the steel pipe sizing, into the cooling tower, through the water cooling, the cooling pipe, it is necessary to be straightened. After straightening by the steel pipe sent to the metal detector (or water pressure test) for internal testing. If the pipe has cracks, bubbles and other problems, will be detected. After the quality of steel pipe but also through rigorous manual selection. After the quality inspection of steel pipe, spray paint with the number, size, production lot number. And suspended by the crane into the warehouse.