Numerical Simulation Analysis Of Residual Stresses And Welding Process Optimization For T91 Steel Pipe Ring Weld

Since China has been experiencing a rapid development in its economy,its need for electricity has also been on the rise day by day.The energetic shortage and envi ronmental pollution issues have been increasingly severe.The most urgent matter at this moment is to promote the thermal efficiency of thermal power plants,thus the requirement for refractory steel's performance becomes more and more strict and demanding,especially in terms with its welding property and thermal strength.After welding,there tends to remain higher residual stress,which may have serious influence on its performance and thus shorten its operation life.It would pose bad effect to operation safety.Therefore,it's becoming more and more crucial to accurately detect the residual stress after welding and take effective measures accordingly based on the measurement.This article illustrates the basic theory on temperature field and stress field relative to welding statistics as well as the simulation and analytic method of statistics.It adopts ABAQUS software to conduct analogue simulation on the welding process of T91 steel pipes.To increase the accuracy of simulation and calculation,it us es JMat Pro software to calculate the physical performance parameters of materials in high temperature and then sets up database.In modeling process,it has refined the grids in welding junction and through editing subroutine DFLUX to conduct simulation of double ellipsoid as the internal heat source of welding pool,it systematically simulate the changing situation of the stress-train field and thermal field of the materials in welding.It has conducted experimental verification on the simulation results o f T91 steel pipes' welding joints.Since the measured data are generally consistent with the former calculation results,it proves that finite element method numerical simulation could effectively forecast the residual stress of annular pipes' welding joints after welding,which may serve as reference for the selection of welding data.Based on the research mentioned above,it selects uniform designed experiment methods and uses Von Mises ' maximum strain as the evaluating indicator before conducting experi mental design and emulation calculation on the six influencing factors,namely,welding current,welding voltage,welding speed,preheating temperature,temperature for post-weld head treatment and holding time.It conducts optimized analysis on the data f rom emulation results and thus receives the welding parameters after optimization.Through experimental verification,it ensures the effectiveness of the parameter optimization.