Numerical Simulation Of Temperature Field And Stress Field Of Ti/Steel Dissimilar Metal Duiing Electron Beam Welding

The paper established a finite element model of Ti/steel butt joints by using ANSYS finite element analysis software. On this basis, respectively, the temperature fields and stress field of Ti/steel joint by using pre-middle layer and Ti/steel joint by electron beam welding directly are simulated. The accuracy of the results is verified.Firstly, respectively, the temperature fields of Ti/steel joint by using pre-middle layer and titanium/steel joint by electron beam welding directly were carried out numerical simulation.both the characteristics of temperature field remained the same, the pool is small, heating rate is fast. And the temperature distribution on both sides is asymmetric, the peak temperature of the node in the same distance from the weld bead is different. It has a big gap. The two results of temperature field were compared and it can be found that after adding the middle layer, the peak temperature of molten pool is significantly low, and the temperature gradient of the two sides is also significantly reduced. To verify the accuracy of the results, thermal cycling curves of the two joints were measured, calculated values and measured values are in good agreement.The melting characteristics of Ti/steel joints added the middle layer were simulated during EBW, during the process,the thickness of layer and thermal effect of partial electron beam were different. Both sides of the weld width decreases with the thickness of the middle layer increasing, , but the Ti side of the pool width is always greater than the steel side. The thickness of the middle layer is not more than 0.7mm. With the partial beam position offsetting to the steel side ,the the weld width of Ti side decreases, the steel side increases, but the position should be controlled between the boundary layer of Cu-Ti and Cu-steel.Finally, using thermal-structural coupled analysis method, the stress field around the joints that the middle layer is added to or not were calculated. both the stress distribution around the joint is consistent, longitudinal residual stress in weld bead is tensile stress, transverse residual stress is compressive stress, and the stress distribution in the two side is asymmetric, longitudinal tensile stress is mainly in the steel side of the weld bead. compared the residual stress results, It can be found that the peak stress after adding the middle layer reduced significantly, and stress distribution is more uniform. Pre-cutting method is used to measure longitudinal residual stress of Ti/steel joints added the middle layer. The measurement results is smaller than the simulation results, but the trend is consistent.