Residual Stress Numerical Simulation Analysis And Welding Process Optimization For Pipe Ring Weld

The pipeline is the modern equipment in a delivery of materials, mainly by the welding shape. The pipeline structure like other welding structure experiences sharply unbalanced heating and cooling process in the process of welding, so producing welding residual stress and deformation after welding. These larger welding residual stress and deformation will affect the carrying capacity, performance of the pipe welding joint or structure, and even lead to fracture. Therefore, the pipeline welding residual stress predicted has very important practical significance. This paper employs the method of combining the numerical simulation and experiment to research regularities of pipe welding residual stress distribution. The research results can provide theoretical basis for engineering application.This paper expounds the basic theory of the temperature field and stress field which is involved in the numerical simulation of welding process. This article chooses the function of heat-structure coupling provided by the ANSYS software to compute the welding temperature field of pipeline girth weld by numerical simulation at first, then chooses indirect coupling method. The simulation results of temperature field as the load are applied to the calculation of stress field analysis. Heat-elastoplastic stress numerical simulation is implemented quickly and conveniently. In order to improve the accuracy of simulation calculation, the material parameters of physical properties at high temperature are processed and selected properly; Welds grid is divided tinily; Double ellipsoid heat source form is chose to the inner heat source of the part of weld pool; Secondary development program by APDL is chose to apply load and complete the solution.The temperature field distribution in different time and the axial and hoop stress field distribution of pipe welding joint are calculated when pipe welding circumferential weld is simulated calculated. The relatively small error of the results of numerical simulation and experimental measurements is to prove that the finite element method can effectively predict the welding residual stress of pipeline girth weld joint. The results of the study can provide reference for the selection of welding process parameters.Based on the study mentioned above, the orthogonal experimental design method is chose to the research method. The Von Mises stress is chose to the evaluation standard.There are four factors chose to design orthogonal test which are arc voltage, welding current, groove clearance and welding speed. Those welding residual stress of the pipeline modeless at various factors and various levels are to numerical analysis by finite element analysis software ANSYS. The parameters about welding process are got corresponding the welding residual stress minimum.