The production process of general seamless steel pipes can be divided into cold drawing and hot rolling. The production process of cold-rolled seamless steel pipes is generally more complex than that of hot-rolled pipes. The billet must first undergo three-roller continuous rolling, followed by sizing tests after extrusion. If there are no surface cracks, the round tube is then cut by a cutting machine into billets of approximately one meter in length. Next, the annealing process begins, where the billet is acid cleaned with acidic liquids. During the acid cleaning, attention must be paid to the presence of excessive bubbling, as this indicates that the quality of the steel pipe does not meet the required standards. Cold-rolled seamless steel pipes are generally shorter in appearance than hot-rolled seamless steel pipes, and their wall thickness is usually smaller than that of hot-rolled pipes. However, they appear brighter and have fewer roughness on the surface, and less burrs on the diameter. The delivery status of hot-rolled seamless steel pipes is typically after hot treatment. After quality inspection, the pipes are hand-picked by staff, then coated with oil on the surface, followed by multiple cold drawing tests. After hot rolling treatment, a piercing test is conducted; if the expansion is too large, it must be straightened. After straightening, the pipes are transported by conveyors to the flaw detection machine for testing, labeled, sorted by specifications, and then stored in the warehouse.
































