Seamless steel pipe is a long strip of steel with a hollow section and no joints around it. The thicker the wall thickness of the seamless steel pipe, the more economical and practical it is. The thinner the wall thickness, the higher the processing cost; its detection and shaping must be processed offline. Therefore, it reflects its superiority in terms of high pressure, high strength, and mechanical structural materials.

Seamless steel pipe can be divided into many types, such as hot-rolled seamless steel pipe, its production process is: round tube billet→heating→piercing→three-roll skew rolling, continuous rolling or extrusion→tube removal →Sizing (or reducing)→cooling→straightening→hydrostatic test (or flaw detection)→marking→storage.

The raw material for rolling seamless steel pipe 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.

The temperature control in the furnace is a key issue. After the round tube blank is released from the furnace, it must be pierced by a pressure punching machine. 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 diameter 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 seamless steel pipe is determined by the outer diameter length 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 seamless steel pipe is cooled, it will be straightened.

There are also cold drawn seamless steel pipes and seamless steel pipes: round tube billets → heating → perforation → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold drawing) Rolling) → billet tube → heat treatment → straightening → hydraulic test (flaw detection) → mark → storage.

The first three steps of the production process of cold-drawn and hot-rolled seamless steel pipes are basically the same. The difference starts from the fourth step. After the round tube blank is hollowed, it must be headed and annealed. After annealing, a special acid liquid should be used for pickling. After pickling, apply oil. Then it is followed by multiple passes of cold drawing and then billet tube, special heat treatment. After heat treatment, it is straightened. After straightening, the seamless steel pipe is sent to the metal flaw detector (or hydraulic test) by the conveyor belt for internal flaw detection.