Numerical Simulation Of Thermal Stability Forming Of Asymmetric An Asymmetric Horizontal Welding

At present, the fillet welding is widely used in large-scale structural components, such as ships, excavators, oil pipelines. In the welding process, liquid metal flow of the weld pool affects the temperature field, weld penetration and weld quality, which has a direct impact on the service life of the structures. The high quality of root-welding is the guarantee of the basic requirements of the fillet weld strength, however, in the asymmetric root-welding, the welding parameters is very sensitive to the back weld width. The temperature field and flow field were analyzed to solve the problem of unstable penetration and poor forming quality, which always happens in asymmetric fillet welding.In order to explore the effect of the welding parameters on welding and improve the quality of forming, the three-dimensional mathematical model of low carbon asymmetric fillet welding were established according to the coupling equations. The models were considered about the surface tension gradient, the electromagnetic force, gravity and the effect of temperature, radiation and convection heat on physical properties of the material.Compared to discuss the effect of welding current on temperature field under the different structure,focus on analysised the effect of the parameters on the asymmetrical angle welding penetration. The effect of the welding position on weld temperature field was discussed, The flow field and the growth pattern of the weld pool was analyzed, and the weld pool geometry under different currents was compared. The asymmetric fillet weld temperature distribution is not uniform,and back weld width changes on the current is very sensitive,the influence of welding current on weld pool shape is significant.The results show that, the thin metal was preferentially penetrated, and with the welding process the weld width of back expanded until the weld beam was full-penetration. The heat affected zones were got from weld experiments, its shape and size agree well with the simulation results, which verifies the validity of the theoretical analysis.