Forming process of straight welded pipe

Big mouth straight seam welded pipe main production process description:

1. Plate probe: After the steel plate used to manufacture large-caliber submerged arc welded straight steel pipe enters the production line, ultrasonic inspection of the whole plate shall be carried out;

2. Edge milling: through the edge milling machine on the two edges of the steel plate for double-sided milling, to achieve the required plate width, plate edge parallelism and groove shape;

3. Pre-bending: pre-bending machine is used to prebend the edge of the plate, so that the edge of the plate has the required curvature;

4. Forming: in the JCO forming machine, the first half of the pre-bent steel plate is pressed into a "J" shape after several steps, and then the other half of the steel plate is also bent into a "C" shape, and finally the formation of the open "O" shape

5. Prewelding: make the formed straight seam welded steel pipe and adopt gas shielded welding (MAG) for continuous welding;

6. Internal welding: longitudinal multi-wire submerged arc welding (up to four wires) is used to weld the inner side of the straight steel pipe;

7. External welding: longitudinal multi-wire submerged arc welding is carried out on the outside of the straight seam submerged arc welded steel pipe;

8. Ultrasonic inspection I: 100% inspection of the inner and outer welds of the straight seam welded steel pipe and the base material on both sides of the weld;

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

10. Expanding diameter: the full length of submerged arc welded straight seam steel pipe is expanded to improve the dimensional accuracy of steel pipe and improve the distribution of internal stress of steel pipe;

11 water pressure test: in the water pressure test machine to expand the diameter of the steel pipe after the test to ensure that the steel pipe meet the standard requirements of the test pressure, the machine has automatic recording and storage function;

12. Chamfering: the inspected steel pipe will be processed to reach the required size of the pipe end groove;

13. Ultrasonic inspection II: Ultrasonic inspection is carried out again one by one to check the defects that may occur after the diameter expansion and water pressure of the straight welded steel pipe;

14. X-ray inspection II: the steel pipe after expanding and hydrostatic test for X-ray industrial television inspection and tube end weld film;

15. Magnetic particle inspection of pipe end: This inspection is carried out to find defects of pipe end;

16. Anti-corrosion and coating: qualified steel pipe shall be anti-corrosion and coating according to user requirements.