The prefabricated submerged arc steel pipe fittings and assemblies in the processing plant must be completed, that is, all the welds have been welded, the flange joints are installed, and all the flange bolts of the long-term backing plate are worn and tightened. The comparison design value of the external dimension deviation of the submerged arc steel pipe assembly cannot exceed the specified standard.
(1) Hydraulic test: The expanded steel pipes are inspected one by one on the hydraulic testing machine to ensure that the steel pipe meets the test pressure required by the standard. The machine has automatic recording and storage functions;
(2) Diameter expansion: expand the total length of the submerged arc steel pipe to improve the dimensional accuracy of the steel pipe and improve the distribution of internal stress of the steel pipe;
(3) X-ray inspection II: X-ray industrial television inspection and tube end weld filming of the steel pipe after the expansion and hydraulic test;
(4) Pipe end magnetic particle inspection: this inspection is carried out to find the pipe end defects;
(5) X-ray inspection I: X-ray industrial television inspection of the inner and outer welds, using an image processing system to ensure the sensitivity of flaw detection;
(6) Inspect the inner and outer welds of the spiral steel pipe and the base materials on both sides of the weld;
(7) Sonic inspection Ⅱ: Perform sonic inspection again one by one to check the possible defects of the longitudinally welded steel pipe after diameter expansion and water pressure;
(8) Chamfering: Process the pipe ends of the steel pipes that have passed the inspection to meet the required pipe end groove size;
(9) Anti-corrosion and coating: Qualified steel pipes shall be anti-corrosion and coating according to user requirements.
After understanding these standards and testing, we will check steel pipes are more biased when purchasing steel pipes in the future.