Hot rolled seamless steel pipe, thick walled seamless pipe

① The main production process of hot-rolled seamless steel pipes (△ main inspection process):

Preparation and inspection of pipe blank △ → Heating of pipe blank → Perforation → Rolling of pipe → Re heating of steel pipe → Diameter reduction → Heat treatment △ → Straightening of finished pipe → Finishing → Inspection △ (non-destructive, physical and chemical, bench inspection) → Storage

② The main production processes of cold-rolled (drawn) seamless steel pipes are:

Preparation of raw materials → Acid washing and lubrication → Cold rolling (pulling) → Heat treatment → Straightening → Finishing → Inspection

The production process of general seamless steel pipes can be divided into two types: cold drawing and hot rolling. The production process of cold-rolled seamless steel pipes is generally more complex than that of hot rolling. The pipe blank first needs to be subjected to three roll continuous rolling, and after extrusion, it needs to be tested for sizing. If there is no response crack on the surface, the round pipe needs to be cut by a cutting machine to a length of about one meter. Then enter the annealing process, which requires acid washing with an acidic liquid. During acid washing, attention should be paid to whether there are a large number of bubbles on the surface. If there are a large number of bubbles, it indicates that the quality of the steel pipe does not meet the corresponding standards. Visually, cold-rolled seamless steel pipes are shorter than hot-rolled seamless steel pipes. The wall thickness of cold-rolled seamless steel pipes is generally smaller than that of hot-rolled seamless steel pipes, but the surface looks brighter than thick walled seamless steel pipes, with less roughness on the surface and fewer burrs on the diameter