Large-diameter LSAW steel pipe production process mainly explained: 
1. plate probe: used to manufacture large diameter submerged arc welded steel pipe joints straight after entering the production line, the first full-board ultrasonic testing; 


2. Milling: Milling machine through the two-sided edge of the milling plate, so as to meet the requirements of the plate width, the plate sides parallel to the groove shape and degree; 


3. Pre-curved side: the use of pre-bending machine pre-bending plate edge, the edge of the plate has to meet the requirements of curvature; 


4. Forming: in the first half of JCO molding machine after the pre-bending step after several stamped steel, pressed into a "J" shape, and then the other half of the same steel plate bent, pressed into a "C" shape, forming the final opening The "O"-shaped 


5. Pre-welding: make a straight seam welded steel pipe after forming and using gas welding seam (MAG) for continuous welding; 


6. Inside weld: a tandem multi-wire submerged arc welding (up to four wire) on the inside straight seam welded steel pipe; 


7. Outside weld: a tandem multi-wire submerged arc welding on the outside LSAW steel pipe welding; 


8. Ultrasonic testing: inside and outside of the straight seam welded steel pipe weld and weld both sides of the base material 100% inspection; 


9. X ray inspection: 100% weld on the inside and outside of the X-ray industrial TV inspection using image processing system to ensure detection sensitivity; 


10. Expansion:For submerged arc welding and straight seam steel pipe length hole diameter in order to improve the size precision of steel tube, and improve the distribution of stress in steel tube;


11. Hydraulic test: On the hydraulic test machine for steel after expanding by-root test to ensure that the steel pipe to test pressure requirements of the standard, the machine has an automatic recording and storage capabilities; 


12. Chamfering: the steel pipe inspection conducted after the end of processing to the pipe end beveling size requirements.