Carbon Steel Seamless Steel Tube - Royal Group

1. Hot rolling (extrusion seamless steel pipe) : round tube blank → heating → perforating → three-high diagonal rolling, continuous rolling or extrusion → stripping → sizing (or reducing) → cooling → straightening → hydrostatic test (or inspection) → marking → storage
The raw material of rolling seamless tube is round tube billet, round tube embryo is cut and processed by cutting machine with the growth of about 1 meter blank, and sent to the furnace by conveyor belt heating. The billet is fed into a furnace and heated to about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is the key problem. After the round tube billet comes out, it is perforated by the pressure punch. Generally, the most common perforator is the conical roll perforator. This kind of perforator has high production efficiency, good product quality, large perforating diameter and can wear a variety of steel. After perforation, the round tube billet is successively rolled by three high diagonal, continuous rolling or extrusion. After extrusion, the pipe should be removed for sizing. The caliper rotates into the steel embryo through a conical drill at high speed to punch holes and form steel pipes. The inner diameter of the steel pipe is determined by the outer diameter length of the caliper drill bit. After sizing the steel pipe, it enters the cooling tower and is cooled by spraying water. After cooling the steel pipe, it will be straightened.
2. Cold-drawn (rolled) seamless steel pipe: round tube blank → heating → perforation → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → blank tube → heat treatment → straightening → hydrostatic test (inspection) → marking → storage.
The rolling method of cold drawing (rolling) seamless steel pipe is more complicated than that of hot rolling (extrusion) seamless steel pipe. The first three steps of their production process are basically the same. The difference from the fourth step, round tube blank after punching, to head, annealing. After annealing, special acidic liquid is used for pickling. After pickling, oil is applied. This is followed by a special heat treatment of the rebillet tube after multiple cold drawing (cold rolling). After heat treatment, it is straightened.