A Survey of Spiral-welded Steel Pipe Fabrication at Home and Abroad

This paper analyses the spiral-welded steel pipe fabrication both at home and abroad. By comparing the physical and chemical performances of base materials, it is pointed out that, in terms of strength, ductility and weldability, the X65 and X70 low alloy steel pipes made abroad are more applicable for the current requirements of oil transportation than the A₃ and 16Mn steel pipes made in China. Alloying of multiple microelements in the cause of rolling process is a major measure to improve steel quality. High strength and low alloy steel shall be adopted to prevent plate from bending during rolling process. Pipe size will no longer be affected during weld clearance adjustment by changing the fixed joint to hinge joint between overbridge and rotary table of the pipe forming mechanism in pipe fabricating machine. The replacement of outside former with inside one can reduce the residual stress in the formed pipe, resulting in smaller after-deformation, therefor, the pipe geometric size is guaranteed-and the quality of pipe fabricated improved. The urgent task for the domestic industry of pipe fabrication is to speed up the upgrading of the old machines and the theoretical studies on pipe formation.