SSAW Pipe

　　The seamless steel pipe is made of ordinary and high-quality carbon structural steel (Q215-A to Q275-A and 10 to 50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid and acid resistant steel. 　　 Seamless steel tubes have hollow sections and are used in large quantities as pipes for transporting fluids, such as pipes for transporting petroleum, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, the steel pipe has a lighter weight when it has the same bending and torsional strength, and is an economical section steel. The material of the seamless steel pipe is different and its use is different.

　　Hot rolling, as the name suggests, the temperature of rolled piece is high, so the deformation resistance is small to achieve large deformation. Take rolling of steel plate for example, the general thickness of continuous casting slab is about 230mm, and after roughing mill and finishing mill, the final thickness is 1~20mm. At the same time, due to the small thickness ratio of steel plate, the dimension accuracy is relatively low, it’s not easy to cause shape problem. 　　 Advantage 　　It can destroy the microstructure of ingot casting, grain refinement of steel and eliminate microstructure defects, so that make steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel no longer is isotropic; Formation of bubbles, cracks and loose when pouring can also be welded under high temperature and pressure. 　　The technological process of hot-rolled seamless pipe 　　round billet→heating→perforation→extrus...

　　The so-called seamless steel tube yield strength refers to the yield limit when the seamless steel tube yields, that is, the stress against the slight plastic deformation. External forces greater than this limit will permanently disable the part and will not recover. 　　The external factors that affect the yield strength of seamless steel tubes are: temperature, strain rate, and stress state. As the temperature decreases and the strain rate increases, the yield strength of the material increases, especially the body-centered cubic metal is particularly sensitive to temperature and strain rate, which leads to low temperature embrittlement of the steel. The effect of the stress state is also important. Although the yield strength is an essential indicator of the intrinsic properties of the material, the stress state is different and the yield strength values are different. 　　The intrinsic factors affecting the yield strength of seamless steel tubes are: bonding bond, organization, s...

　　 Seamless steel tube heat treatment is divided into three categories: 　　(1) Final heat treatment to meet the performance requirements of seamless steel products; 　　(2) heat treatment in the heat treatment state required by users and standards; 　　(3) heat treatment between processes in the steel pipe manufacturing process. 　　The commonly used heat treatment processes for seamless steel tubes mainly include quenching, tempering, normalizing and annealing. For example: casings, oil pipes, drill pipes, line pipes, etc. in oil special pipes, according to the level of steel grade, the normalizing, normalizing and tempering, quenching and tempering processes are adopted accordingly; 　　High-pressure boiler tubes and high-pressure fertilizer pipes often use normalizing, normalizing and tempering, quenching and tempering (thick-walled pipes) and solid solution treatment of austenitic stainless steel pipes; spheroidizing annealing of steel pipes for bearings. 　　Some alloy steel pip...

　　The pickling process acid pickling solution is generally a mixture of various acids, mainly sulfuric acid, nitric acid and hydrofluoric acid, etc. These mixed acids are highly corrosive and have a strong oxidizing property and a high temperature of corrosive medium. This puts high demands on the corrosion resistance of anticorrosive materials. Stainless steel seamless steel pipe pickling production line process from production to waste gas recovery system, there is a strong corrosion state in all aspects, so the choice of anti-corrosion materials is directly related to the environmental recovery system of equipment, workshop floor, trench, waste water and waste gas Normal use of etc. 　　 Seamless steel pipe pickling process 　　The pickling of seamless steel tubes uses solvents and emulsions to clean the surface of welded steel pipes for low-pressure fluid transport to remove oil, grease, dust, lubricants and similar organic matter, but it does not remove rust, scale, etc. from the ...

　　According to different production methods, seamless steel tube can be divided into hot rolled tube, cold rolled tube, cold drawn tube and extruded tube. 　　1. Hot-rolled seamless pipes are generally produced on automatic rolling mills. The solid tube blank is inspected and the surface defects are removed, cut into the required length, centered on the end face of the perforated end of the tube blank, then sent to a heating furnace for heating and perforated on the punching machine. At the same time, the perforation is continuously rotated and advanced. Under the action of the roll and the head, a cavity is gradually formed inside the tube blank, which is called a capillary tube. It is sent to the automatic pipe mill for further rolling. Finally, the whole machine is uniform in wall thickness, and the sizing machine is sizing to meet the specification. The production of hot-rolled seamless steel tubes by continuous rolling mills is a more advanced method. 　　2. If you want to obtain ...

　　Hot rolled seamless steel pipe , what advantages and disadvantages? Seamless steel tube after hot rolling, grain refinement of steel, destruction of ingot casting structure, and eliminates the defects of microstructures, the steel pipe dense tissue, mechanical properties improved. Before steel pipe in the presence of bubbles, cracks and loose, after hot rolling will be welding under high temperature and high pressure. 　　Although hot rolling seamless steel pipe has many advantages, but its shortcomings must be clear, steel pipe after hot rolling, nonmetallic inclusions in steel is pressed into sheets, and the stratification occurs. Layered make the steel along the thickness direction of the tensile performance deteriorated significantly, in the weld contraction appear torn between the layers. 　　Steel after hot rolling, must have advanced technology, if the technology, however clearance, steel pipe in hot rolling of uneven cooling caused by the residual stress. The residual stress ...

    First, how to prevent thermal expansion and contraction     If this process is extremely slow and the temperature difference is not large, after cooling, it can basically be restored to its original shape, for example, placing an open-air steel plate on the noon evening; if this process is more rapid, it will be remnant due to the expansion of the steel that is forced by the warming. Deformation, after the temperature is restored, the deformation will not be restored, the warping is inevitable, such as the welding process, and if the gas welding is used to correct the deformation technology.     Second, how to prevent thermal expansion and contraction in buildings     Seamless steel tube play a huge role in construction and engineering. Seamless steel tube are subject to thermal variability, especially when they are used to transport natural gas, water, and petroleum on pipelines. Due to the fact that the liquid is often hot and deforme...