Research On Simulation For Forming The Large Diamater Lsaw Pipes With Four-point Bending JCO Process

With the increasing of the countries in the world demand for oil, natural gas，thelongitudinal-seam submerged arc welded(LSAW) pipe as the main carrier of energytransport, and its demand is also increasing. The four-point bending JCO forming which isbased on traditional three-point bending JCO forming process research, uses four-pointbending springback as the theoretical framework. Four-point bending JCO forming used aprogressive multi-step compression molding, which has too many parameters and a longprocess line. This study utilized the method of numerical simulation study of the formingprocess. Through the simulation values are compared with the experimental results, thereliability of the simulation analysis is verified.First, based on four-point bending theory, the two-dimensional finite elementsimulation model of board blank four-point bending was established. The reasonableparameters of the finite element simulation were determined and the deformingcharacteristics were investigated using numerical simulation. Then the study analyzed theimpact of punch fillet radius, die fillet radius, slab thickness, punch span and die span onthe influence law of forming force and bending radius.Second, based on the specifications for pipe forming of262.64.7(mm) asexample, continuous simulation system for four-point bending JCO forming process hasbeen established. Through the comparison between the simulation results andexperimental results, the correctness of the simulation model and the feasibility of theprocess were verified. The characteristics of stress and strain field of four-point bendingJCO forming was analyzed and its deformation characteristics were revealed. The finalforming characteristics of steel tube for different bending times were discussed.Finally, the four-point bending forming limit condition was raised. Using finiteelement simulation model of board blank four-point bending, the four-point bending JCOforming limit was analyzed. By numerical simulation, the study obtained the ultimatebending radius and the limit reduction under differing molding condition. The impact ofthe pitch of punch and die, and die fillet radius on the influence law of four-point bending JCO forming limit was discussed in this thesis.Through the computer simulation, the longitudinal-seam submerged arc welded pipefour-point bending JCO forming regularity has been summarized. It provided a reliablebasis for further research and engineering application.