Seamless steel tube production process:
1. The main production process of hot rolled seamless steel tube (the main inspection procedure):
Tube blanks preparation and inspection: Delta tube to tube billet heating, perforation to rolling pipe to steel pipe reheating, fixed (reduction) diameter heat treatment delta > product tube straightening, finishing to test Delta (non-destructive, physical and chemical, bench inspection)
2, cold rolling (drawing) seamless steel pipe production process:
Billet preparation, pickling, lubrication, cold rolling (drawing), heat treatment, straightening, finishing, and testing.
The production process of general seamless steel tubes can be divided into two types: cold drawing and hot rolling. The production process of cold rolled seamless steel tubes is generally more complicated than hot rolling. First, three roll continuous rolling is needed for tube billets, and then the sizing test is carried out after extrusion. If the surface does not respond to cracks, the circular tube must be cut through the cutting machine, cutting the billet with a growth of about one meter. And then enter the annealing process. The acid should be pickled by acid liquid. When the acid is washed, we should pay attention to whether there is a large amount of bubbling on the surface. If there is a lot of bubbling, the quality of the steel pipe can not reach the corresponding standard. The appearance of cold-rolled seamless steel tubes is shorter than that of hot-rolled seamless steel tubes. The wall thickness of cold-rolled seamless steel tubes is generally smaller than that of hot-rolled seamless steel tubes, but the surface looks more brighter than seamless steel tubes with thick walls, and the surface is not too rough, and there is not much burr on the caliber.
The delivery status of hot-rolled seamless steel tubes is generally delivered after hot rolling. Hot rolled seamless steel pipe must undergo strict manual selection after the quality inspection. After the quality inspection, the surface should be oiled. After that, several cold drawing experiments will be followed. After hot rolling, perforation experiments will be carried out. Straightening and straightening should be carried out if the piercing enlargement is too large. After straightening, the transmission device is then transmitted to the flaw detecting machine to carry out the flaw detection experiment. Finally, the label is attached and the specification is arranged to be placed in the warehouse.
The seamless tube is made of steel ingots or solid tube billets by perforation, and then made by hot rolling, cold rolling or cold chowing. The three roll skew rolling, continuous rolling or extrusion, then tube drawing, diameter reducing or reducing diameter, cooling to straightening, water pressure test (or flaw detection), marking and warehousing. The specification of seamless steel pipe is expressed by outer diameter * millimeter of wall thickness.
The outer diameter of hot rolled seamless pipe is generally larger than 32mm and the wall thickness is 2.5-200mm. The outer diameter of the cold rolled seamless steel pipe can reach 6mm, the wall thickness can reach 0.25mm, and the outer diameter of the thin-walled tube can reach 5mm wall thickness less than 0.25mm, and the cold rolling ratio is higher than the hot rolling dimension accuracy.
Generally, seamless steel pipes are made of hot rolled or cold-rolled 16Mn, 5MnV and other low alloy structural steels, such as 10, 20, 30, 35, 45, or 40Cr, 30CrMnSi, 45Mn2, 40MnB, etc. Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid conveying pipes. 45, 40Cr and other medium carbon steel seamless pipe for manufacturing mechanical parts, such as cars and tractors of the force parts. Generally, the strength and flattening test of seamless steel pipe should be ensured. Hot rolled steel pipes are delivered in hot rolling or heat treatment; cold rolling is delivered in heat treatment.
Hot rolling, as the name suggests, the temperature of the rolled piece is high, so the deformation resistance is small, and large deformation can be achieved. Taking the rolling of steel plate as an example, the thickness of continuous casting billets is about 230mm, and after rough rolling and finishing rolling, the final thickness is 1~20mm. At the same time, because of the small width to thickness ratio of steel plate, the requirement of dimensional accuracy is relatively low, and the shape problem is not easy to appear. The requirements for the organization are generally controlled by controlled rolling and controlled cooling, that is to control the rolling temperature and final rolling temperature of finish rolling. Round tube billet, heating, piercing, heading, annealing, acid pickling, oiling (copper plating), multi pass cold drawing (cold rolling), tube to heat treatment, straightening, water pressure test (test), marking, storage.
Seamless steel tube has hollow cross section, and it is widely used as a conduit for conveying fluid, such as pipelines for transporting petroleum, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, the steel tube is lighter in weight and has the same bending and torsional strength. It is a kind of economic section steel. It is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffolding used in construction and so on. Steel pipe has been widely used in manufacturing hours.