1. In the forming process of thick-walled spiral pipe, the deformation of steel bar is small, even the residual stress is small, and there is no scratch on the surface. Processing steel pipe has greater flexibility in the range of diameter and wall thickness. Especially in the production of high-grade thick-walled steel pipe, especially in the large-diameter thick-walled pipe, it has advantages that other processes can not match, and can meet the requirements of more users'pipe specifications.


2. Pre-welding after internal and external welding (fine welding) process can be carried out in the best position. It is not easy to produce staggered edges, partial and incomplete penetration welding defects, and easy to control welding quality.


3. Integral mechanical expansion can effectively improve the dimensional accuracy of steel, improve the stress distribution in steel pipe, avoid stress damage caused by corrosion, and be beneficial to the construction site welding.


4. The steel pipe needs 9 quality inspections of 100%. The whole process of steel production can be effectively inspected and monitored to ensure the quality of SAW pipe.