Spiral submerged arc welded pipe adopts double-sided submerged arc welding process, that is, welding is performed on both the inner and outer sides of the steel pipe at the same time to ensure the welding quality and the overall strength of the steel pipe.

Submerged arc welded spiral steel pipes are increasingly popular in oil and gas, slurry transportation, urban construction and other industries due to their high pressure-bearing capacity, low resistance, low temperature resistance, corrosion resistance, and convenient installation and maintenance.

After the steel plate enters the production line, it first undergoes full-plate ultrasonic inspection;

1.Edge milling: Use an edge milling machine to perform double-sided milling on both edges of the steel plate to achieve the required plate width, plate edge parallelism and bevel shape;
2.Pre-bending: Use a pre-bending machine to pre-bend the board edge so that the board edge has a required curvature;

3.Forming: On the JCO forming machine, first half of the pre-bent steel plate is stamped into a "J" shape through multiple steps, and then the other half of the steel plate is similarly bent and pressed into a "C" shape, and finally the open " O" shape

4.Pre-welding: joint the formed steel pipes and use gas shielded welding (MAG) for continuous welding;

5.a. Internal welding: Use tandem multi-wire submerged arc welding (up to four wires) to weld on the inside of the steel pipe;
   b. External welding: Use longitudinal multi-wire submerged arc welding to weld on the outside of the spiral submerged arc welded steel pipe;

6.Ultrasonic inspection I: 100% inspection of the internal and external welds of spiral steel pipes and the base metal on both sides of the welds;

7.X-ray inspection I: 100% X-ray industrial television inspection of internal and external welds, using an image processing system to ensure the sensitivity of flaw detection;

8.Diameter expansion: The entire length of the straight seam steel pipe is expanded to improve the dimensional accuracy of the steel pipe and improve the distribution of stress within the steel pipe;

9.Hydraulic pressure test: The expanded steel pipes are inspected one by one on a hydraulic pressure testing machine to ensure that the steel pipes meet the test pressure required by the standard. The machine has automatic recording and storage functions;

10.Chamfering: Process the pipe end of the steel pipe that has passed the inspection to achieve the required pipe end bevel size;

11.Ultrasonic inspection II: Conduct ultrasonic inspection again one by one to check for defects that may occur after diameter expansion and hydraulic pressure of spiral seam welded steel pipes;

12.X-ray inspection II: Conduct X-ray industrial television inspection and pipe end weld photography on the steel pipe after diameter expansion and hydraulic pressure test;

13.Pipe End Magnetic Particle Inspection: This inspection is performed to detect pipe end defects;

14.Anti-corrosion and coating: Qualified steel pipes are anti-corrosion and coated according to user requirements.

In addition to the above inspection items, according to API standards and other related standards and the special requirements of some users, it is also necessary to conduct destructive inspections and other inspections on steel plates and steel pipes, including random inspections of the physical and chemical properties of raw materials entering the factory, and 100% appearance inspection of steel plates. .

We provide spiral submerged arc welded pipes with diameters of 219mm-3500mm, these are only part of the specifications.

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