Study On The Development Of Three-dimensional Weld Pool Surface Of TIG Welding Process

The surface of the welding pool directly reflects the shape, the appearance and the inherent quality of the weld seam. Therefore, this paper mainly carries out a series of research work from the surface of TIG welding pool. The relationship between the surface height of the welding pool and the reflection laser is established by the reflection image of the structure laser with the surface morphology of the welding pool. The obtained two-dimensional image of the welding pool and the corresponding geometric parameter data The surface morphology of the pool was restored.With this method, the three-dimensional surface morphology of the molten pool can be obtained in real time, and the liquid metal flow in the molten pool can be controlled to improve the controllability of the welding process without increasing the welding production cost,and reflect the richer three-dimensional information,It is of great theoretical and practical significance to obtain the beautiful weld, improve the quality of welding and improve the intelligent welding.Firstly, the observation experiment platform of TIG welding pool is introduced. The reflection reflection of the surface of the welding pool surface and the reflection characteristics of the beam on the surface of the welding pool and the surface of the workpiece are proposed. The three-dimensional surface of the tank surface and the three-dimensional surface recovery algorithm of the TIG welding pool based on the grid structure laser are used to observe the evolution of the three-dimensional surface of the fixed-point TIG welding pool. The recovery algorithm of the surface of the molten pool is obtained by the recovery algorithm The three-dimensional morphology of the molten pool surface. The mathematical model of three-dimensional surface of fixed - point TIG welding pool was established by FLOW-3D software, and the numerical analysis was carried out. By comparing the shape of the molten pool after welding, the test results and numerical simulation results are basically consistent.Secondly, the influence of welding step (current step and velocity step),pulse TIG welding and droplet impact on the three-dimensional surface of TIG welding pool is explored from the experimental point of view, and the combination of simulation and experiment TIG welding pool surface dynamic evolution process analysis. The results show that the deformation of the molten pool changes little from the low current step to the high current. When the high current step reaches the low current, the deformation of the welding pool changes obviously. The difference between the step currents is larger,The more the deformation of the welding pool surface.From the low speed step to the higher speed, the number of grid laser in the pool to reduce the pool surface area decreases first and then increase, and finally stabilized; from high speed step to lower speed, the grid laser The number of baths on the pool increases,the pool surface area increases.Through the analysis of the surface of TIG wire filling bath, it can be found that there is a certain error between the morphology of the solder bath and the results of the test and the recovery result, and the overall morphology is consistent. From the numerical simulation analysis, it is concluded that the droplet drop process will cause the free surface of the molten pool to fall.The droplet enters the molten pool and changes the distribution of the original temperature field and the flow field of the molten pool, causing serious deformation of the free surface of the molten pool , So that the free surface of the pool with damping vibration over time.Finally, the influence of different welding speed on the three-dimensional surface evolution of TIG welding bath is analyzed, and the three-dimensional surface of TIG welding pool under different welding speed is calculated according to the grid laser reflection image collected by the acquisition system. And reconstructed and compared with the test results. In order to study the formation mechanism of TIG welding humps under speed limit, the mathematical model of TIG welding hump was established by means of FLOW-3D. The temperature field, flow field and free surface of TIG welding pool were analyzed And the reasons for the formation and formation of the surface of the rapidly moving TIG weld pool are also analyzed. By analyzing the distribution of liquid particles in the molten pool after the solidification of liquid metal, it was found that the particles were pre-distributed in the surface layer, and the part of the molten pool was located in the hump and partly in the vicinity of the weld center or near the weld line. Welding heat coupling, the flow of liquid metal is not the surface flow.