1. Thick-walled spiral pipe forming process, the steel deformation even small residual stress, surface does not produce scratches. Processing of steel in the diameter and wall thickness of pipe sizes range, greater flexibility, especially in the production of high-grade steel thick-walled pipe, particularly large diameter thick-walled tube aspect has the incomparable advantage of other processes to meet more user requirements in terms of pipe specifications;
2. The use of internal and external welding (fine welding) process after the first pre-welding, can be implemented in the best position welding, less prone to the wrong side, partial and incomplete penetration welding defects, easy to control weld quality;
3. Overall mechanical expanding can effectively improve the dimensional accuracy of steel, and to improve the distribution of internal stress of the steel pipe, so as to avoid damage due to stress caused by corrosion, it is also conducive to the construction site welding;