Straight seam steel pipe production process

　　Straight seam steel pipe production process. According to the production process, straight seam steel pipes can be divided into high-frequency straight seam steel pipes and submerged arc welded straight seam steel pipes. Submerged arc welded straight seam steel pipes are further divided into UOE, RBE, JCOE steel pipes according to their different molding methods. The following describes the most common molding processes for high-frequency straight seam steel tubes and submerged arc welded straight seam steel tubes.


　　Submerged arc welding process 1. Panel inspection: After the steel plate used to manufacture the large diameter submerged arc welded straight seam steel pipe enters the production line, the whole board ultrasonic inspection is first carried out; 2. Milling edge: double-sided milling of the two edges of the steel plate by the edge milling machine To achieve the required plate width, edge parallelism and groove shape; 3. Pre-bend: use the pre-bending machine to pre-bend the edge of the plate to make the edge of the plate meet the required curvature; 4. Molding: Forming in JCO The machine firstly presses half of the pre-bent steel plate through multiple steps, presses it into a "J" shape, and then bends the other half of the steel plate into a "C" shape, and finally forms an open "O" shape. Pre-welding: joints of straight seam welded steel pipes after forming and continuous welding by gas shielded welding (MAG); 6. Internal welding: using longitudinal multi-wire submerged arc welding (up to four wires) on the inside of straight seam steel pipes Welding; 7. External welding: welding by longitudinal multi-wire submerged arc welding on the outside of straight seam submerged arc welded steel pipe; 8. Ultrasonic inspection I: 100% of the inner and outer welds of the straight seam welded steel pipe and the base material on both sides of the weld % inspection; 9. X-ray inspection I: 100% X-ray industrial TV inspection of internal and external welds, using image processing To ensure the sensitivity of flaw detection; 10. Expanding diameter: Expand the diameter of the submerged arc welded straight seam steel pipe to improve the dimensional accuracy of the steel pipe and improve the distribution of stress in the steel pipe; 11. Hydraulic test: in the hydraulic test On-board inspection of the expanded steel pipe to ensure that the steel pipe meets the test pressure required by the standard. The machine has automatic recording and storage functions. 12. Chamfering: The steel pipe after passing the inspection is processed at the pipe end to meet the required pipe. End groove size; 13. Ultrasonic inspection II: Ultrasonic inspection is carried out again and again to check for defects that may occur after straightening and water pressure of straight seam welded steel pipes; 14. X-ray inspection II: after expansion and hydrostatic test X-ray industrial TV inspection and tube end weld filming; 15. Tube end magnetic powder inspection: carry out this inspection to find tube end defects; 16. Anti-corrosion and coating: qualified steel pipe according to user requirements for anti-corrosion and coating Floor.