Differences between seamless steel pipes and welded steel pipes

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Many people are likely still unclear about the differences between seamless steel pipes and welded steel pipes; today, we will provide some information on this topic. Seamless steel pipes: 1. In terms of appearance, the difference between seamless steel pipes and welded pipes is that welded pipes have weld beads inside their interior, whereas seamless pipes do not. 2. Seamless steel pipes can withstand higher working pressures; welded steel pipes generally have a pressure rating of around 10 MPa. Nowadays, welded steel pipes are also available in a seamless version. 3. Seamless steel pipes are formed in one step during cold rolling. Welded pipes must be electrically welded after production, with spiral welding and straight welding being the common methods. Smaller-diameter welded pipes are mostly manufactured using straight-seam welding, while larger-diameter welded pipes are generally produced with spiral welding. The welding method for spiral-welded pipes is similar to that of straight-seam pipes; however, straight-seam pipes inevitably have numerous cross seams, which increases the likelihood of welding defects. Moreover, the weld metal at these cross seams is often under triaxial deformation, increasing the risk of cracks forming. Seamless steel pipes are superior in terms of performance, and naturally, their price is higher as well. Seamless steel pipes, spiral-welded pipes: 4. Seamless steel pipes are hollow rectangular stainless steel sections that are often used as pipelines for transporting fluids such as crude oil, natural gas, water, liquefied gas, and steam. Additionally, given their lower weight while maintaining the same strength in terms of bending, torsion, and compression resistance, they are also widely used in the manufacture of mechanical parts and structural elements for construction projects. It is also commonly used in the manufacture of various strategic weapons, gun barrel riflings, bullets, etc. 5. The key is that the forming processes are different. Ordinary steel pipes, such as those used for drinking water supply, are generally made by bending flat sheets of metal and then welding them together; you can see a weld line on them ； Those with a larger diameter are generally welded in a spiral pattern. Seamless steel pipes are generally formed by extruding molten iron that has been accumulated through circular double-slit openings, using processes such as drawing; as a result, there is no welding involved. In terms of its properties, especially its ability to withstand pressure, it offers a significant improvement over ordinary steel pipes; therefore, it is often used in high-pressure machinery. Such as pipeline connections for hydraulic machinery and equipment. The welding area of ordinary steel pipes is their weak point, and the quality of welding is a key factor that affects their overall properties. Those who have lived in northern regions know all too well the experience of water supply pipes or heating pipes bursting due to freezing in winter, with the breaks usually occurring at the welding points.