seamless pipe manufacturing process

Rainbow-Steel Industry Co., Ltd. will show you the manufacturing process of seamless pipe:

① Main production process of hot rolled seamless pipe (△ main inspection process):

Preparation and inspection of test tube


② Main production process of cold-rolled (drawn) seamless steel pipe:


Billet preparation → pickling and lubrication → cold rolling (drawing) → heat treatment → straightening → finishing → inspection


Generally, the production process of seamless steel pipe can be divided into drawing and hot rolling. Generally, the production process of cold-rolled seamless steel pipe is more complex than hot rolling. First, the steel pipe is rolled in three rolls, and then the extrusion sizing test is carried out. If the surface does not respond to the crack, the pipe is cut in the over cutting machine and cut into pieces about one meter long. Then enter the annealing process. Pickling and pickling should be used. Acid pickling should be used. Attention should be paid to whether there is a large amount of foam on the surface of the pickling. If there is a large number of bubbles, the quality of the steel does not meet the corresponding standards. The appearance of cold-rolled seamless steel tube is shorter than that of hot-rolled seamless steel tube. The thickness of cold-rolled seamless steel tube is usually smaller than that of hot-rolled seamless steel tube, but the surface of cold-rolled seamless steel tube is thicker than that of thick wall seamless steel tube. The surface should not be too rough and the caliber should not be too large.


The delivery state of hot-rolled seamless steel pipe is usually the hot-rolled state after heat treatment. The hot-rolled seamless steel pipe shall be selected strictly by hand by the quality control personnel, oiled after quality inspection, and then cold drawn for many times. After hot rolling, the hole diameter of the experiment shall be too large to be corrected. After straightening, the transmission device is sent to the flaw detector for detection. Finally, the specifications will be labeled and placed in the warehouse after being sorted out.


Round pipe → heating → piercing → three roll inclined rolling, rolling or extrusion → pipe dismantling → size adjustment (or reduction) → cooling → straightening → hydrostatic test (or flaw detection) → marking → storage seamless steel pipe is made of ingot or solid pipe perforated by capillary tube, and then made by hot rolling, cold rolling or cold turntable. The specification of seamless steel pipe is indicated by outer diameter * mm mm.


The outer diameter of hot-rolled seamless pipe is generally larger than 32mm, the wall thickness is 2.5-200mm, the diameter of cold-rolled seamless pipe can be 6mm, the wall thickness can be 0.25mm, and the wall thickness of 5mm thin-walled pipe diameter is less than 0.25mm, which is higher than the dimension accuracy of hot-rolled and cold-rolled seamless pipe.


The general purpose of seamless steel pipe is 16Mn, 5mnv low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB bonding steel, such as hot rolling or cold rolling. 10, 20 and other low carbon steel seamless pipes are mainly used for fluid pipes. 45,40 Cr and other medium carbon steel seamless pipes are used to make mechanical parts, such as stressed parts of automobiles and tractors. Seamless steel pipes are usually used to ensure strength and flattening tests. Hot rolled steel pipes shall be delivered in hot rolling or heat treatment state and heat treatment shall be carried out in cold rolling state.


As the name implies, hot rolling has higher locomotive temperature, so it has less deformation resistance and can achieve a lot of deformation. Taking steel plate rolling as an example, the thickness of continuous casting slab is generally about 230mm, and the final thickness after rough rolling and finishing rolling is 1-20mm. At the same time, because the length diameter ratio of steel is small, the requirement for dimensional accuracy is relatively low, and it is not easy to have plate like problems, mainly to control the convexity. For the structure requirements, rolling control is generally used to achieve the control, that is, to control the finishing rolling temperature and finishing rolling temperature. Round tube → heating → piercing → annealing → pickling → oiling (copper plating) → multi pass cold drawing (cold rolling) → → billet heat treatment and straightening → hydrostatic test (test) → marking → storage.