Numerical Simulation Of Residual Stress In Welding Joint

Welding is a complicated physicochemical process which involves in electromagnetism, heat transferring,metal melting and solidifying,phase transition,welding stress and deformation and so on.In order to get high quality welding structure,we have to control these factors.If welding process can be simulated with computer, we will easily determine the best design, procedure method and optimum welding parameter.Based on summing up others'experience, employing numerical calculation method,this paper researches how to realize the 3D dynamic simulation of welding residual stress when weldment is cooled,then uses the research result to simulate the welding process of plate surfacing and test and verify.In this paper studied how to attain the distribution regulation of welding residual stress by finite element method.The welding plate is 10mm in thickness, the material is 16MnR which is low-alloy steel,and it is welded with v-shape groove butt weld form.The subject establishes model of the finite element based on the welding plane,use the newly-increased mold of the MSC.Marc2005 softwares which is the WELD PATH to define the weld path.The simulation results about the welded residual stress are almost identical with the measuring results by testing methods.The paper offers the two dimensional distribution curves of residual stresses,the results shows:(1) In the all test plates,the residual stress of the welded joint and its adjacent are all tensile stress,as the distance far from the welded jiont,the residual stress changes compressive stress; the residual stress is probably the maximum on the weld central surface of plane.(2) The change of groove angle influnted to the residual stress of test plate greatly when three-layer welding, the longitudinal and cross direction residual stress of 60°groove welded jiont and nearly bead all higher than 50°groove welded jiont and nearly bead; In the middelof the test plate ,the maximumσ_x is 135. 2MPa and the maximumσ_y is 352.3MPa in the 60°groove of the test palte,the maximumσ_x is 92. 3MPa and the maximumσ_y is 291.5MPa in the 50°groove of the test palte.(3) In the 60°groove and the 50°groove of the test plate when one-layer welding, the residual stress are all compressive stress which are all changed below zero from the weld center line 10mm distance.(4) In all test plates, the longitudinal direction residual stress of welded jiont and nearly bead all higher than the cross direction residual stress,the directiion of maximum principal stress deviates the longitudinal direction.