The difference between hot-rolled tube and cold-drawn tube
According to different production methods, it can be divided into hot rolled pipe, cold rolled pipe, cold drawn pipe and extruded pipe.
1. Hot rolled seamless pipes are generally produced on automatic rolling mills. The solid tube blank is inspected and the surface defects are removed, cut into the required length, centered on the end face of the perforated end of the tube blank, then sent to a heating furnace for heating and perforated on the punching machine. At the same time, the perforation is continuously rotated and advanced. Under the action of the roll and the head, a cavity is gradually formed inside the tube blank, which is called a capillary tube. Then send it to the automatic pipe rolling machine to continue rolling. Finally, the whole machine is uniform in wall thickness, and the sizing machine is sizing to meet the specification. The production of hot-rolled seamless steel tubes by continuous rolling mills is a more advanced method.
2. If you want to obtain a seamless tube of smaller size and better quality, you must use cold rolling, cold drawing or a combination of the two. Cold rolling is usually carried out on a two-roll mill in which the steel pipe is rolled in an annular hole type composed of a variable-section circular hole groove and a stationary tapered head. Cold drawing is usually carried out on a single-chain or double-chain cold drawing machine of 0.5 to 100T.
3. The extrusion process is to place the heated tube blank in a closed extrusion cylinder, and the perforated rod moves together with the extrusion rod to extrude the extrusion from the smaller die hole. This method can produce steel pipes with smaller diameters.
