A seamless tube is a long strip of steel with a hollow section and no seams around it
Hot rolling, cold drawing, hot spreading
According to different production methods, it can be divided into hot rolling pipes, cold rolling pipes, cold pulling pipes, and extrusion Guandeng.
1.1. Hot rolled seamless tubes are generally produced on automatic rolling units. The solid tube billet is inspected and cleared of surface defects, truncated to the required length, centered on the end surface of the tube billet perforation, and then sent to a heating furnace for heating and perforation on the perforator. At the same time, the perforation continuously rotates and advances. Under the action of the roll and the top, the inner cavity of the tube billet gradually forms a cavity, which is called a wool tube. Send it to the automatic mill and continue rolling. In the end, the whole machine is thick and the diameter is determined by the diameter machine to meet the specifications. The production of hot-rolled seamless steel pipe by continuous rolling pipe unit is a relatively advanced method.
1.2 To obtain seamless tubes of smaller size and better quality, cold rolling, cold drawing or a combination of both must be used. Cold rolling is usually carried out on a two-roller mill, and the steel pipe is rolled in a circular hole formed by a variable section hole slot and a stationary conical head. Cold draws are usually performed on single-chain or double-chain cold pullers of 0.5 to 100T.
1.3. The hot tube blank is placed in a closed extrusion cylinder by extrusion method. The perforated rod moves with the extrusion rod to squeeze the extruder out of the smaller mold hole. This method can produce smaller diameter steel pipes.