LSAW Carbon Steel Pipe 558.8*6.35

Why can the quality of welds and structures be guaranteed? The quality core of 558*6.35 LSAW carbon steel pipe originates from the collaborative application of longitudinal submerged arc welding technology and precision forming technology, which fundamentally avoids weld defects and strengthens structural integrity. Its manufacture adopts UOE or JCOE forming process, with hot-rolled carbon steel plate as raw material, pre-bent, gradually formed into tubular shape, and then welded by double-sided submerged arc welding. Submerged arc welding technology covers the welding area with granular flux, which insulates the air and stabilizes the arc, effectively reduces the defects such as porosity and cracks, and the weld metal crystallizes evenly, and the weld strength can reach more than 95% of the base metal. At the same time, the steel pipe of this specification will be expanded after forming, which will not only control the outside diameter tolerance within 0.5%, but also eliminate the welding residual stress and avoid the later service deformation. The whole process needs to pass ultrasonic, X-ray nondestructive testing and water pressure test to ensure that the weld is defect-free and the structural performance is stable.

How do carbon steel materials and specifications match the working conditions? 558*6.35 LSAW steel pipes are mostly made of conventional carbon steel such as API 5L Gr.B, X42, etc., which are suitable for most medium and low pressure transportation conditions with both mechanical properties and economy. Through microalloying treatment and controlled rolling and cooling process, the yield strength of carbon steel can reach above 290MPa, the tensile strength is between 415 and 550 MPa, and the impact work at -20℃ is ≥30J, which has good toughness and impact resistance. The combination of 6.35mm wall thickness and carbon steel material makes the steel pipe of this specification withstand the pressure within 10MPa, and is suitable for transportation of natural gas, crude oil, industrial wastewater and other media. In the light corrosive environment such as damp, saline and alkali, the corrosion resistance can be improved by coating FBE fused epoxy coating or 3PE composite coating, and the service life can be extended to more than 30 years. Compared with seamless steel pipe, it meets the requirements of working conditions, reduces the cost by 20%-30%, and has obvious cost performance advantage.