Abstract:Steel pipes made of a whole piece of metal with no seams on the surface are called seamless steel pipes. According to the production management method
Steel pipes made of a whole piece of metal with no seams on the surface are called seamless steel pipes. According to the production management method of the enterprise, seamless pipes are divided into hot-rolled pipes, cold-drawn pipes, extruded pipes, cold-rolled pipes, top pipes, etc. . Seamless steel pipes can be divided into round pipes and special-shaped pipes according to different cross-sectional shapes. Special-shaped pipes have various structural shapes such as oval, square, hexagon, triangle, star and fin. Seamless steel pipes can be used as boiler pipes, drill pipes for petroleum engineering geology, cracking pipes for petrochemical industry, bearing pipes, and high-precision steel pipes for automobiles, tractors, and aviation in China.
Seamless steel pipes are widely used. According to different uses, seamless steel pipes can be divided into three types of supply:
1. Supply according to chemical composition and mechanical properties;
2. Supply based on mechanical performance only;
3. According to the water pressure test supply.
Seamless steel pipes have a hollow cross section and are widely used as pipelines for oil, gas, water and other fluids and some solid materials. Compared with solid steel such as round steel, steel pipe is an economical section steel with the same bending and torsion strength and relatively light weight.
Seamless steel pipes are widely used in the manufacture of structural parts and mechanical parts such as oil drill pipes, automobile transmission shafts, bicycle frames, steel structure scaffolds, etc. It can effectively improve the utilization rate of steel pipe materials, simplify the design and manufacturing technology, and save materials and processing time. It has been widely used in steel pipe manufacturing under various needs.
The general production process of seamless steel pipes can be divided into cold drawing and hot rolling. The production technology and process design of cold-rolled seamless steel pipes is generally more complicated than that of hot-rolled steel pipes. First, the tube blank is rolled with three rolls, and the sizing test is carried out after extrusion. If there is no reaction crack on the surface, the tube is cut into a blank of about one meter with a cutting machine, and then enters the annealing process, which can be pickled with acidic ionic liquid . When pickling, pay attention to a large number of bubbles on the surface. If there are not many bubbles, it means that the quality management of the steel pipe does not meet the corresponding standards. Cold-rolled seamless steel pipes look shorter than hot-rolled seamless steel pipes. The wall thickness of cold-rolled seamless steel pipes is usually smaller than that of hot-rolled seamless steel pipes, but the surface looks not much different from thick-walled seamless steel pipes. There is not much surface roughness and too many burrs in the diameter.
The delivery time of hot-rolled seamless steel pipes is generally hot-rolled and delivered after heat treatment. Hot-rolled seamless steel pipes should be strictly selected by the staff after the quality inspection. After the quality inspection, the surface should be oiled, and then subjected to multiple cold drawing tests, and then to the piercing test after the hot-rolling treatment. If the aperture is too large, it should be straightened and corrected. Finally, label it and put it in the warehouse to complete the delivery.