The spiral seam welded steel pipe is in the welding process, the welding torch and the welding seam are in the relative motion of the combination of the rotary motion and the linear motion, and the weld seam is spiral. Therefore, it is hoped that countries or industries will formulate such standards as soon as possible for designers and manufacturers.Straight seam arc welded steel pipe commonly used standard GB12771-2008 "stainless steel welded pipe for fluid transport", HG50237. It is characterized by high production efficiency and low production cost, but the metallurgical bonding of welded joints is incomplete, the quality of welds is poor, and the overall mechanical properties are poor. The specification range of SY/T5037 is DN250^DN2500, and the wall thickness is from 15mm to 5.Continuous welding (forging) steel tubes Continuous welding (forging) steel tubes are heated in a heating furnace, and then the formed edges are welded together with a pressurizing method to form a straight seam Steel pipe. Among them, GB12771 standard specifications range from DN6 ~ DN560, wall thickness from 0.0mm.According to the different types of welds, arc welded steel pipe can be divided into two kinds of longitudinal welded pipe and spiral welded pipe.0mm to 20. . convenient. The applicable medium is water, gas, air, heating steam and other common fluids. Current welded pipe is only used for water and compressed air systems in pressure axial fan pipes. Therefore, it is generally applicable to non-toxic medium pipelines with a design temperature of 0°C to 200°C and a design pressure of no more than 1.1 ~ 4 "austenitic stainless steel welded pipe" and so on.0 MPa.However, spiral welded pipe production can be continuous operation, high production efficiency, high material utilization, and facilitate large-scale production.0mm total of 29 kinds of specifications, material grades are 1Cr18Ni9, 0Cr19Ni9, 00Cr19Ni11, 0Cr18Ni10Ti, 0Cr17Ni12Mo2, 00Cr17Ni14Mo2 a total of 12 species. Its characteristic is that the welded joint achieves a complete metallurgical bond, and the mechanical performance of the joint can fully reach or approach the mechanical properties of the parent metal. After proper heat treatment and non-destructive inspection, the conditions for the use of arc welded straight seam steel tubes can be used to replace seamless steel tubes. Compared with the straight seam steel pipe, the weld line length is long, and the force of the weld seam is a two-dimensional tensile stress. According to the different protection methods adopted during welding, arc welded steel pipes can be divided into two types: submerged arc welded steel pipes and melted gas shielded welded steel pipes.3mm ~ 14. This is very unlikely. There are three types of materials: Q195, Q215, and Q235.The arc welded steel pipe is a steel pipe produced by the arc welding method. When this type of welded steel pipe is used in design, many manufacturing requirements are often required in the design documents. At present, the commonly used steel pipe standards are SY/T5037 "Spiral Seam Submerged-Welded Steel Pipes for Ordinary Fluid Conveying" and so on.Under normal circumstances, straight seam welded pipe should not be used for extreme or highly hazardous media delivery. At present, China has no carbon steel pipe and alloy steel straight seam arc welded steel pipe standards that are applicable to petrochemical centrifugal fan plants.