Causes for Common Defects of Spiral SAW Pipe Occurring in Shaping Process and Preventative Actions

Taking the production of the Φ1 016 mm×17.5 mm X70 spiral SAW pipes as supplied for the Sichuan-East Gas Transport Pipeline Project as an example, and considering the relationship between shaping and welding processes, the common defects as occur in the manufacturing process of hi-strength, heavy wall spiral SAW pipes (including excessive O.D. deviation, edge displacement, “pouting” and cracking, etc.) are described, and the causes for such defects are analyzed. Accordingly preventative actions are taken. As a result the shaping quality of the pipe is improved, and welding quality and welding speed are enhanced, having reduced the labor intensity of the operators and increased the equipment availability.