The Numerical Simulation Of Welding Residual Stress In Butt Joints With Rare Earth Added

Welding is the important method connecting metal in the modem manufacturing technology.It is effective for refining the microstructure of the deposited metal and improving the mechanical properties to add the rare earth element?La;CeO₂?into the electrode.At the same time,numerical simulation is the low-cost and high-reliability method,determining welding process parameters.With Visual Environment software,the temperature field,stress field,microstructure,displacement and residual stress are numerically simulated during the process of butt-joint multi-layers and multi-passes welding,containing rare earth?La/Ce?.And the results extracted are studied.The 12 simulation projects are designed,and the composition of electrodes and welding speed are different in the each projects.The finite element model of V-groove butt-joint is established with Visual Mesh software.The process parameters of 12 projects are set in process planning wizard with Visual Weld.According to the simulation results,the displacement of No.6 project is the smallest.There are 0.5% La and 0.1% CeO₂ added in the No.6 project.With Visual Viewer software,the thermal cycle curves of feature points and the temperature field cloud pictures during the welding process are extracted.The change rules of the temperature field are summarized.According to the thermal cycle curves,the temperature field change of multi-layers and multi-passes is more complicate.The temperature field of weld bead welded is affected by the weld bead been doing.According to the analysis of stress field distribution cloud during the welding process and the residual stress tendency chart of feature paths,the residual stress of the HAZ and the area near the clamping points is maximum.Comparing the No.6 project,producing minimum distortion,and the residual stress of the integral component in No.1 project,there being not rare earth elements,is higher.According to the graph of phase proportion simulated,there are ferrite and pearlite in the deposited metals.With BX51 M metallography analyzing system,the deposited metals of No.6 project is observed.The ratio between the ferrite and pearlite is measured,and the calculation is consistent with the simulation results.Furthermore,the influence of rare earth element on the deposited metals is analyzed.