Compared with seamless steel pipe, the advantages of longitudinal welded pipe are as follows:


(a) High dimensional accuracy. The diameter and wall thickness of welded steel pipe are much smaller than that of seamless steel pipe. Because strip rolling and tube forming are easy to control, the dimension accuracy is high.
B) Good mechanical properties. The control of welded steel pipe is easy to roll. Welding technology and on-line heat treatment technology can control the performance of the weld, so the elongation of the longitudinal welded pipe is 10% higher than that of the seamless pipe, because the carbon content of the longitudinal welded pipe is 12% lower than that of the seamless pipe.
C) Longitudinal welded steel pipe with high concentricity and uniform wall thickness. After post-weld heat treatment, the microstructure is uniform and has strong collapse ability.
Because of the good ductility of steel, the compression test of the sisterly pipe of the straight sewing machine is better than that of the seamless pipe.
(e) Longitudinal welded pipe has higher impact toughness than seamless pipe.
Longitudinal resistance welded pipe is not welded to different metals, but through strict on-line heat treatment, so the basic performance and material characteristics of welding.