Finite Element Analysis Of Welding Progress For Q345/2Cr13Dissimilar Steel

Based on the welding expert numerical simulation SYSWELD code, Finiteelement method (FEM) was performed on the dissimilar metal butt-joint between Q345low alloy steel and2Cr13stainless steel aiming at the welding temperature field,residual stress and distortion. Considering the form of welding joints and characteristicsof the welding heat process,the finite element analysis model was established.Thedouble ellipsoid heat source volume distribution model was represented and SYSWELDcode function was carried out to fullfill the moving of the heat source on the weld platefor the purpose of simulating the real arc welding process. Adaptive meshing girdtechnique was implemented to separate the geometric model and relationship betweentemperature and material properties like thermal physical properties and mechanicalproperties was considered in the numerical calculation process. The latent heat inducedby phase transformation was investigated and specific heat capacity of mutations wasapplied to calculate the latent heat in simulation process. Material properties at hightemperature were calcaulated through interpolation method and indirect couplinganalysis was applied to modeling thermal-stress behaviour of the welded plate duringthe simulation process. Prediction of temperature variations, residual tress as well astransverse shrinkage and angular distortion were obtained by completely Newton-PullSimpson iterative method in the computation. Through the definition of molten poollength to determine the initial time step, so as to realize the automatic time stepcalculation the code itself and get accurate numerical results.The main contents in the paper were summaried as follows:1) Different lineenergy was applied to medelling the welding process of Q345/2Cr13disimmilar steeland the law of temperature field as well as stress-strain field were discussed.2)Thermo-elastic-plastic FE method was implemented to analysis the differences betweenresidual tress and deformation in ununiform preheating temperature.3) Using differentfiller metals as the welding materials to discuss the influence of different filler metal onthe welding residual stress and distortion of dissimilar metal joints between paltes ofQ345low alloy steel and2Cr13stainless steel.4)Actual welding trails was applied inorder to verify the accuracy of the numerical calculation by comparing the measurementresult with simulation result through testing the thermal cycles of the sample points thathave different distance away from the welding line. This study presented the characteristics of residual stress and distortion in welds ofdissimilar steel weldment by carring out3-D thermal elastic-plastic FEA.Based on theresult in this work, some conclusions can be made as follows:1)Temperature field andresidual tresss field were asymmetric distribution about the welding line when theheterogeneous steel Q345steel and2Cr13stainless steel were welded.The residual tresspeak value on the2Cr13base metal was hight than Q345, but stress distribution areawas narrow than Q345base metal.2) Line energy had significant influence on themagnitude and distribution of residual tress, and residual stress as well as distortiondecreased with the increasing of line energy.3) Different preheating temperature gotdifferent thermal field and the distinction between residual stress and deformation ofununiform conditions was significant.4) Filler metals also have been investigated andits influence on residual stress and deformation was great.5) The values of the ButtFEA Model showed a trend which was in good agreement with the experimental valuesand the values of FE analysis were found reasonable.