Thick-walled Longitudinal Welded Pipe The main production process:

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1. Board exploration: Used to manufacture large diameter submerged arc welded straight seam steel pipe into the production line, the first full-board ultrasonic inspection;

2. Milling: Milling machine for both sides of the plate through the double-sided milling, so as to achieve the required width, edge parallelism and groove shape; 3. Pre-crimp: pre-bending plate pre-bending machine , So that the board has the curvature to meet the requirements;

4. Molding: In the JCO machine first half of the pre-bent steel plate after several step stamping, pressed into a "J" shape, and then the other half of the same curved plate, pressed into a "C" shape, and finally the formation of openings The "O" shape

5. Pre-welding: After forming the straight seam welded steel seam and the use of gas shielded welding (MAG) for continuous welding;

6. Internal welding: using longitudinal multi-wire submerged arc welding (up to four wires) welded straight seam pipe;

7. External welding: the use of longitudinal multi-wire submerged arc welding in the LSAW pipe welding;

8. Ultrasonic testing Ⅰ: 100% inspections of the base metal on both sides of the straight seam welded steel pipe inside and outside the weld and weld;

9. X-ray inspection Ⅰ: Internal and external weld 100% X-ray industrial television inspection, the use of image processing systems to ensure the sensitivity of testing; 10. Expansion: Submerged arc welding of straight steel pipe to expand the full-length Improve the dimensional accuracy of the steel pipe, and improve the distribution of stress within the steel pipe 11. Hydrostatic test: On the hydraulic pressure testing machine on the expanded diameter of the steel pipe to test to ensure that the steel pipe to meet the standards required test pressure, the machine has automatic Record and store functions

12. Chamfering: the steel pipe after the test tube end processing to achieve the required pipe end bevel size;

13. Ultrasonic inspection II: Ultrasonic inspection is carried out again and again to check the defects that may occur after the straight seam welded steel pipe is enlarged in diameter and water pressure. 14. X-ray inspection II: X-ray inspection Industrial television inspection and pipe end welding filming;

15. Tube Magnetic Particle Inspection: Perform this inspection to detect tube end defects;

16. Anticorrosion and Coating: After passing the steel pipe according to user requirements for corrosion and coating.

Longitudinal welded pipe materials commonly used in China are generally Q235A, Q235B, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, 16Mn, 20 #, Q345, L245, L290, X42, X46, X70, X80 and so on.

Longitudinal welded pipe in the country mainly used in water works, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction. For liquid delivery: water supply, drainage. For gas delivery: gas, steam, liquefied petroleum gas. For structural purposes: for piling pipe, as a bridge; pier, road, building structure with the tube.