According to different production methods of cold drawn seamless precision steel tubes, seamless steel tubes can be divided into hot rolled tubes, cold rolled tubes, cold drawn tubes, and extruded tubes.
If you want to obtain seamless steel tubes with small size and good quality, you must use cold rolling, cold drawing or a combination of the two. Cold rolling is usually carried out in a two-roll mill. The steel pipe is rolled in a circular pass composed of a variable-section round hole groove and a fixed conical head. Cold drawing is usually carried out in the single-chain or double-chain cold-drawing machine commander of 0.5 to 100T.
The extrusion method is to put the heated tube blank in a closed extrusion cylinder. The perforated rod moves with the extrusion rod to make the extrusion extruded from the smaller die hole. This method can produce steel pipes with smaller diameters.