SSAW Pipe

　　 Advantages of LSAW pipes 　　It can destroy the casting structure of steel ingots, refine the grain of steel, eliminate the defects of structure, make the steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel pipe is no longer isotropic to some extent; the dumping bubble, the crack and the loose stratum can also be welded at high temperature and high pressure. 　　 LSAW pipeline 　　Sawing defect 　　1, the residual stress caused by unequal cooling. The residual stress is the internal self balancing stress in the absence of external force. All cross-sections of hot rolled steel have such residual stresses. The greater the size of the general section, the greater the residual stress. Although the residual stress is self balanced, the steel structure may have adverse effects on the external force, such as deformation, stability, fatigue and so on. 　　2, after welding, the non-metallic inclusions...

　　SSAW pipeline is allowed to use in Italy. 　　In Canada, LSAW pipe and SSAW pipe is regarded as equally important, but in practice, SSAW pipe accounted for about 70% in the main line. 　　SSAW pipe was rarely used in the former United States, Japan and Germany. With the establishment of more and more oil and gas transport lines, seamless limitations and limits of the size of the welded tubes are slowly emerging. These countries are also increasingly using LSAW pipe and SSAW pipe. 　　Russia fully affirmed the advantages of SSAW pipe, so the main line is generally preferred SSAW pipe. 　　According to the forming process, the SSAW pipe has a lot of residual tensile stress (Maximum up to 200 ~ 300 Pa). While in the process of UOE forming process, there is an enlarged diameter. The surface of that compressive residual stress is - 200 ~- 300M Pa. 　　In the process of mechanical expansion, UOE tube has higher dimensional accuracy than SSAW pipe. 　　The weld length of SSAW pipe is long...

　　The method for quality inspection of LSAW pipe , in which the physical method is the most commonly used inspection method, physical examination is a physical phenomenon to determine or check the application of the method. 　　 Magnetic force 　　Magnetic flaw detection can only find the shortcomings of the appearance and appearance of the magnetic straight seam welded pipe. The disadvantages can only be quantitatively analyzed. The nature and depth of the flaw can only be estimated based on experience. Magnetic flaw detection is the use of magnetic field to discover the leakage of magnetic longitudinal weld seams. According to the method of measuring magnetic flux leakage, it can be divided into magnetic powder method, magnetic induction method and magnetic recording method, in which the magnetic powder method is the most widely used. 　　Soak inspection 　　Penetration testing is the use of some liquid physical properties such as permeability to detect and display defects, including...