Integrated Simulation And Analysis Of The Residual Stress Field For Large-sized Straight Welded Pipe Processing With JCOE Technology

Straight welded pipe processing with JCOE (Progressive forming process of “J”forming,“C” forming and “O” forming, reduced gap, welding, and mechanicalexpanding processes) technology is characterized by long distance, large diameter, highpressure resistance, and large wall thickness. The forming process, with low cost, andsmall-sized mold, is the main direction of straight seam welded pipe in the future.However, the current research on residual stress of JCOE welded pipe is not perfect andthe complex residual stress from the JCO forming process leads to severe cuts welded pipeservice life. This study deals with three-dimensional continuous integrated simulation ofthe “JCO forming–welding–mechanical expanding” process of JCOE pipes using Marcsoftware. The residual stress distribution trend of welded pipe and the influence rule of theexpanding ratio are investigated in this study.Continuous model of the JCO forming (Progressive forming process of “J”forming,“C”forming “,O”forming, and reduced gap) is established to simulated the process ofthe JCO welded pipe. The evolution rule of the residual stress field in each step in theprocess of JCO forming is obtained; The effects rule of the residual stress in the process ofreducing gap are analyzed, and getting the residual stress distribution regularity of JCOtube blank before expanding. In order to obtain various JCO tube blank which withdifferent opening degree, we adjust the forming process and then analysis the openingdegree influence of residual stress to the JCO tube billet.The continuous integration simulation on JCO forming process, joint process,welding process of large-sized straight welded pipe is carried out based on Marc.Joint effects of stress on welding residual stress were studied and then Analysis the weldresidual stress field evolution of post weld tube blank and before expanding the freestate tube. Get the weld residual stress peak area of the state JCO pipe and summed up theinfluence rule of opening to weld residual stress field.The continuous integration simulation on JCO forming process, joint process,welding process and mechanical expanding process of large-sized straight welded pipe iscarried. The integrated simulation result compared with the simulated results of ellipse model and the actual production results shows that: The integrated simulation resultsof the outline of the cross section, the tube wall thickness distribution and the residualweld stress distribution is more close to the result of the actual production. At the sametime, Analysis the influence of relative punch radius on residual stress and get the bestexpanding die radius; Analysis the expanding ratio effects on the weld residual stress; Fitout the empirical formula between ratio of expanding diameter and JCOE pipecircumferential residual stress peak; get the residual stress distribution of the welded pipewith different opening degree after expanding.