According to the different manufacturing methods of cold drawn seamless splicing precision steel tubes, seamless can be divided into hot rolled tubes, cold rolled tubes, cold drawn tubes, extruded tubes and so on.
The production process of cold drawn seamless steel pipe is: round pipe billet → heating → perforation → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → billet pipe → heat treatment → straightening → Hydraulic test (detection) → mark → storage.
The quality of cold drawn seamless pipe steel mainly depends on his workmanship
There are many ways to produce cold-drawn seamless steel tubes. Here are a few of them.
1.Hot-rolled and cold-drawn seamless steel tubes are generally produced on automatic tube rolling mills. The solid billet is checked and cleared of surface defects, cut into the required length, centered on the end face of the billet perforation, then sent to the heating furnace for heating, and perforated on the perforator. Under the action of the roll and the top, a cavity is gradually formed inside the billet, which is called capillary. It is then sent to the automatic pipe mill to continue rolling. Finally, the wall thickness of the whole machine is equalized, and the sizing machine is used to calibrate the diameter, which meets the requirements of specifications. It is an advanced method to produce hot-rolled seamless steel pipe by continuous pipe rolling mill.
2. In order to obtain seamless pipes with smaller size and better quality, cold rolling, cold drawing or combination of the two methods must be adopted. Cold rolling is usually carried out on a two-roll mill. Steel tubes are rolled in an annular pass consisting of a circular groove with variable cross-section and a fixed conical head. Cold drawing is usually carried out on single-chain or double-chain cold-drawing machines of 0.5-100T.
3. The extrusion method is to place the heated tube blank in a closed extrusion cylinder, and the perforating rod moves with the extrusion rod to extrude the extruded part from a smaller die hole. This method can produce steel pipes with smaller diameter.