1. study: used in the manufacture of large diameter longitudinal submerged arc welded steel pipe plate after entering the line, first the whole plate ultrasonic testing;

2. milling: by milling machine for plate two-edge milling on both sides, so as to meet the requirements of the Board width, parallel to the edge and Groove shape;

3. bending: bending machine for plate bending and curvature of the plate edge has to meet the requirements;

4. forming: JCO molding machine after the first bend on half of the plate after repeatedly stepping punch, pressed into a "j" shape, the other half of the plate the same again bent, pressed into the "c" shaped, eventually forming the opening "o" shaped

5. welding: body of longitudinal welded pipe joint and the use of gas shielded arc welding (MAG) in a continuous welding;

6. welding: by columns multiple wire submerged arc welding (up to five) on the inside straight seam steel pipe welding;

7. welding: using multiple wire submerged arc welding in the vertical column lateral longitudinal submerged arc welded pipe welding;

8. ultrasonic examination I: for longitudinal welded pipe inside and outside welds and sides of the weld 100% check;

9. x-ray examination I: 100% x ray industrial television check inside and outside welds using image processing system to ensure the detection of sensitivity;

10. expanding: the straight seam submerged arc-welded steel tubing length expanding to improve the dimensional accuracy, and improve the State of stress distribution in steel tube;