Three-dimensional Numerical Simulation Of Temperature Fields And Stress Fields In The Multi-pass Welding Of Mid-thick Plates

Because the process of thick plates multi-pass is very complicated, whether temperature fields and stress fields are predicted correctly is the key point to get good quality of the weld. In this paper, the finite element analysis of temperature fields and stress fields in the multi-pass welding of mid-thick plates is accomplished based on the ANSYS, and this paper analyzes how temperature fields in the different time and residual stress of the different directions are and explains the reasons why they are distributed like that. What's more, it is shown that the simulation results are in good accordance with the experiments in the study. This paper can assist people to choose the right welding parameters in butt-welding quickly, saving a lot of time and money.With the ANSYS the paper brings forward a double heat sources model. The double heat sources include a heat resource of Gaussian surface flux distribution and a heat source of double ellipsoidal distribution,and the ratio of the powers is 3 : 2. Based on this heat source model the result is consistent with the actual situation. In order to know the welding effective radius, welding speed and convective heat-transfer coefficient how to affect temperature fields in the butt-welding, the paper utilized bead-on-plane welding. At the same time, it realized the process of pass filling dynamical welding by using "Element Birth and Death" in the ANSYS. And in view of the electrode having similar characters with the workpieces, the paper made the study simpler, taking the same thermal physical parameters in both the mid-thick plates and the weld, and this method that deals with thermal physical parameters of the electrode not only make the arithmetic simpler but also does not affect the precision of the finial results.In the temperature fields, the paper analyzed the curves of thermal cycle at the different cross sections, and the results are accordant with the actual situation. The width of the weld was about 9mm and the depth was about 4.6mm. In the stress field, transverse residual stresses had a balance between tensile stresses and compressive stresses on the weld, and in the same time, longitudinal residual stresses got a balance between tensile stresses and compressive stresses on the cross section of the weld. Because the temperature was distributed asymmetrically on the cross section of the weld, when the thick plate was bended, the results shown there was close between the computed values and measured values.