Raw material selection and forming process of seamless steel pipe

The raw material for seamless steel pipe rolling is a round tube blank, which is cut by a cutting machine into a billet with a length of more than 1 meter, and sent to a furnace for heating through a conveyor belt.

The billets are fed into the furnace and heated at about 1200 degrees Celsius. Generally, the more common punching machine is the conical roller punching machine. This kind of punching machine has high production efficiency, good product quality, large amount of perforation and expansion, and can wear a variety of steel grades. After perforation, the round tube blank is successively cross-rolled, continuously rolled or extruded by three rolls. After extrusion, the tube should be removed and sizing. The sizing machine rotates into the steel billet at high speed through the conical drill bit to punch holes to form steel pipes.

The inner diameter of the steel pipe is determined by the outer diameter of the drill bit of the sizing machine. After the steel pipe is sizing, it enters the cooling tower (through water spray cooling/air cooling, depending on the mechanical properties of the steel pipe). After the steel pipe is cooled, it will be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or hydraulic test) by the conveyor belt for internal flaw detection.

When choosing seamless steel pipes, you can choose your own suitable steel pipes from the aspects of material size and mechanical properties.

Generally, seamless steel pipes are made of high-quality carbon-structured steels such as 10, 20, 30, 35, and 45, low-alloy structural steels such as 16Mn and 5MnV, or alloy steels such as 40Cr, 30CrMnSi, 45Mn2, and 40MnB, which are hot-rolled or cold-rolled. Seamless steel pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transmission pipelines. Seamless steel pipes made of medium carbon steels such as 45 and 40Cr are used to manufacture mechanical parts, such as the stressed parts of automobiles and tractors.