FEM Simulation and Theoretical Calculation of Deforming Displacement for JCO Forming of High Grade Heavy-Wall LSAW Pipes

The stress and strain distribution of φ1 219 mm×33 mm X80 high grade heavy-wall longitudinal submerged arc welded (LSAW) pipes during JCO forming process was simulated by finite element methods (FEM). The results show that both the stress and strain distributed symmetrically from the middle of the up die, and both the maximum equivalent stress and the maximum equivalent strain located at inner and outer surface crossing to the middle line of the pressed plate. With the increase of absolute value of displacement loads, the equivalent stress and strain also increased, and when the displacement load h=18 mm, the maximum equivalent strain of the section of the pressed plate had been yielded. And the deforming displacement of the forming process was calculated as h=17.8 mm theoretically which was very close to the results of FEM simulation.