has the following advantages:
(1) Steel pipes of the same width can be used to produce steel pipes of different diameters. In particular, large diameter steel pipes can be produced from bismuth strip steel.
(2) The stress of the spiral weld is smaller than that of the straight seam, which is only 75-90% of the straight welded pipe, so it can bear a large pressure.
(3) The size is accurate. Generally, the diameter tolerance is less than 0.12%, the deflection is less than 1/2000, and the ellipticity is less than 1%. Generally, the sizing and straightening process can be omitted.
(4) Continuous production: In theory, it is possible to produce steel pipes without infinite length, with small loss of cutting head and tail cutting, which can improve the utilization factor of metal by 6~8%.
(5) Flexible operation, easy to change the variety (compared with straight seam welded pipe
(6) The equipment is light in weight, with low initial investment, and some units are made to flow, which can be directly produced on the construction site where the pipeline is laid.