Seamless steel pipes are rolled from solid tube blanks after being perforated.
The production and manufacturing methods can be divided into hot-rolled pipes, cold-rolled pipes, cold-drawn pipes, extruded pipes, etc. according to different production methods. Extruded pipes are divided into seamless steel pipes and welded steel pipes, and seamless steel pipes can be divided into hot-rolled seamless steel pipes and cold-rolled seamless steel pipes.
Hot-rolled seamless steel pipes are generally produced on automatic pipe rolling units. After inspection and removal of surface defects, the solid tube blank is cut into the required length, centered on the perforated end of the tube, and then sent to the heating furnace for heating and piercing on the piercing machine. While piercing, the solid tube continuously rotates and advances under the action of the roller and the head. , a cavity is gradually formed inside the tube blank, called a gross tube, and then sent to the automatic tube rolling machine for continued rolling. Finally, the wall thickness is evened by the leveling machine, and the diameter is determined by the sizing machine to meet the specification requirements. The continuous tube rolling unit is used to produce hot-rolled seamless tubes. Sealing steel pipes is a more advanced method. Generally, pipe blanks with a diameter of more than 800mm are processed into pipe blanks with steel ingots or medium plates.
Cold-rolled (drawn) seamless steel pipes are generally produced on cold-rolled pipe machines. A tube blank is sent to the bright punching machine for piercing, and then sent to the flash butt welding machine. The two welding end faces are heated close to each other, then sent to the de-pipe machine to pull out the tube, and then sent to the straightening machine for straightening. After straightening, it is sent to the first, second, third, fourth, The five-stage extrusion machine extrudes and deforms each section of the tube blank to obtain the finished product after mechanical processing.