Application and manufacturing process of thick-walled seamless steel pipe

What is thick wall steel pipe?
The steel pipe with the ratio of the outer diameter of the steel pipe to the wall thickness is less than 20 is called the thick-walled steel pipe.

Application of thick-walled seamless steel pipe: 

Mainly used as petroleum geological drilling pipe, cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural pipe for automobile, tractor, aviation, etc.

Manufacturing process of thick-walled seamless steel pipe:

Hot rolling (extruded seamless steel pipe): round tube billet → heating → perforation → three-roll cross-rolling, continuous rolling or extrusion → pipe removal → sizing (or diameter reduction) → cooling → straightening → hydraulic test (or flaw detection)→marking→warehousing

The raw material for rolling seamless tubes is a round tube blank, which is cut by a cutting machine into a billet with a length of about 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. The fuel is hydrogen or acetylene. Furnace temperature control is a critical issue. After the round tube blank is released, it will be perforated by a pressure perforator. 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 and is cooled by water spray. After the steel pipe is cooled, it will be straightened.