Production process of the seamless steel pipe

　　1.Production process of the hot-rolled seamless steel pipe are as below:pipe preparation and inspection△→Billet heating → perforation → pipe rolling → steel reheating→ Fixed (minus) diameter → Heat treatment △ → Straightened finished product → Finished → Inspection △ (Non-destructive testing, physical and chemical testing, and Taiwanese inspection) → Incoming storage

　　2.Production process of the cold rolled (pulled out) seamless steel pipe: billet preparation → Pickling lubrication → Cold rolling (pulling) → heat treatment → straightening → finishing → inspection

　　General seamless steel pipe production process can be divided into two kinds of cold drawing and hot rolling. The production process of cold rolled seamless steel pipe is generally more complicated than hot rolling. The pipe blank must be firstly rolled by three rollers, and it must be pressed after extrusion. In the sizing test, if the surface does not respond to cracks, the circular tube must be cut by a mower to cut a blank having a length of about one meter. Then enter the annealing process, annealing with acidic liquids for pickling, pickling should pay attention to the surface whether there is a lot of blistering, if there is a large number of blisters generated that the quality of the steel can not meet the corresponding standard. Appearance of cold-rolled seamless steel pipe is shorter than hot-rolled seamless steel pipe, cold-rolled seamless steel pipe wall thickness is generally smaller than the hot-rolled seamless steel pipe, but the surface looks brighter than thick-walled seamless steel pipe, the surface is not too More rough, caliber does not have too many glitches.