Simulation Of TIG Melt Pool Of Aluminum Alloy With The External Magnetic Field

The article research the influence factors of the welding pool flow field,temperature field and morphology of welding pool.Firstly, building the mathematical model of TIG welding pool and studying theinfluence of welding parameters to the flowing of liquid metal and the shape ofwelding pool. The result show that as the current increase the,the penetration andwelding width have increased, penetration increased significantly, under the conditionof all other parameters remain unchanged. The result of test and simulation have thesame trend about the changing of welding pool shape; Single change welding speed,as welding speed increases, the penetration and welding width is reduced, themaximum temperature is reduced. The simulation and experimental results are thesame basically; After a period of time, the temperature field reaches the quasi-steadyand distributes symmetrical; The major way of heat transfer is thermal convection inthe welding pool. The liquid metal flow to the edge from the center resulting to theincreasing of penetration on the welding pool surface and flow to the center from theedge resulting to the increasing of welding width in the bottom of welding pool.To study the influence of various driving force, the article simulate the change offlow and temperature field, when the model just have one of the driving force, forexample the flotage, electromagnetic force and surface tension. the result show thatthe flotage drive the liquid metal flowing to the edge from the center,that increase thewelding width and reduce the penetration; The electromagnetic force drive the liquidmetal flow to the center from the edge in the surface and flow to the welding bottomfrom the surface in the central axis,that increase the penetration and reduce thewelding width; The minus surface tension drive the liquid metal flow to the edge fromthe center and the plus surface tension is in contrast. The welding pool flow fields aredistributed two levels, the up level is impacted by the surface tension and the bottomlevel is impacted by the electromagnetic obviously, when all the driving force is acton the welding pool. So the surface tension is the first, then is electromagnetic force, the last is flotage, to the extent of impact to the flow field on the surface.Electromagnetic force is the first, surface tension is the second,and flotage is the laston the bottom level.External magnetic field rotates the liquid metal on the surface and increases thewelding width with a divergency and play a agitation role in the welding pool; Theagitation impact is obvious, when the magnetic field intensity is in range of0.01T-0.02T and the frequency is in the range of1HZ-2HZ. With the increase ofmagnetic field intensity, the depth decrease and the width increase. With the increaseof magnetic field frequency, weld width increase, decrease after first penetrationincreases first and then.