Plate Ultrasonic Inspection： Each plate is first full-plate ultrasonic inspected after entering the process
　　b. Plate Edge Milling： The Plate edges are milled by Edge Milling Machine to obtain the required width, parallelism and bevel angles;
　　c. Plate Edge Crimping：The two edges of the plate are crimped at the Crimping Machine to get the required radius;
　　d. Forming： The first half of the plate is fed step by step into the Pipe Forming Press to form the plate into a" J "shape. Then another half of the plate is pressed step by step to form the plate into" C "shape. The last stroke is to press the plate into an open "O" shape;
　　e. Continuous Tack Welding： The two edges of the open seam pipe should be brought together by tack welding machine then welded by tack welder using metal active-gas arc welding (MAG) process;
　　f. Inside Welding： The pipe is welded from inside of the pipe by multipass tandem submerged-arc welding (max. four wires);
　　g. Outside Welding： The pipe is welded from outside of the pipe by multipass tandem submerged-arc welding;
　　h. Ultrasonic Testing I： The welded area on both sides of the weld are 100% tested by automatic ultrasonic tester .