The maximum operating pressure that a seamed pipe can generally withstand is within 20 kg/cm², which is considered the safest range for use. Seamed pipes are typically used for low-pressure fluids such as water, gas, and compressed air. In contrast, seamless pipes can withstand ultra-high pressure, and their wall thickness increases accordingly, depending on the pressure requirements. Seamless pipes are generally used for high-temperature and high-pressure equipment such as high-pressure oil pipes and boiler pipes. There are also seamless pipe fittings designed for structural purposes, which depend on the specific design requirements.
Seamed steel pipe fittings and seamless steel pipe fittings are classified based on their processing forms. Seamed steel pipe fittings are typically welded, while seamless steel pipe fittings are produced through cold drawing and hot rolling.
Stainless steel seamless pipe fittings are long strips of steel with a hollow cross-section and no seams. The thicker the wall of the product, the more economical and practical it is. Conversely, thinner walls result in higher processing costs. The process used in manufacturing the product limits its performance. Generally, seamless steel pipe fittings have lower precision, with uneven wall thickness, reduced brightness of the inner and outer surfaces, higher costs for fixed lengths, and difficulties in removing pitting and black spots. Detection and shaping of these pipes must be processed offline. Nevertheless, seamless pipes excel in applications requiring high pressure, high strength, and mechanical structural materials.
There are differences in the chemical composition between stainless steel seam pipes and stainless steel seamless pipes. The steel composition for seamless pipes meets the basic requirements of ASTM standards. In contrast, the steel used for seam pipes contains chemical elements tailored for welding, such as silicon, sulfur, manganese, and controlled amounts of ferrite. These elements help produce a weld melt that transfers heat efficiently during welding, ensuring a complete and strong weld. Steel pipes lacking these specific chemical compositions, such as seamless pipes, may encounter various unstable factors during welding, making it difficult to achieve a firm and complete weld.
