According to the production standards for spiral welded pipes, the main inspection/control items for spiral welded steel pipes include:
Dimensions: outer diameter of steel pipe, wall thickness, ovality, bending degree, pipe end verticality,
Length and appearance quality: determination of excess weld height, wrong edge, steel pipe surface, delamination, inclusions, and weld defects
chemical composition
Welded joint tensile test
Hydrostatic pressure test
Acid etching inspection
NDT
There is no corresponding production standard for straight seam welded pipes.
Generally, the spiral welded pipe unit adopts the online continuous inspection method to ensure the welding quality of the weld, which is another important feature of the spiral welded pipe production that is different from the straight seam welded pipe production. Continuous inspection is beneficial to the monitoring of welding defects, the stability of welding quality, and the assurance of welding grades.
Due to the limitations of the production process, it is extremely difficult to achieve continuous and uninterrupted inspection of straight seam welded pipes. This will increase the probability of welding hidden dangers and quality problems, and even affect the overall reliability of pipeline operation in the future.
