Research On High Frequency Welding Quality And Heat Dissipation Performance Of Aluminum Alloy Thin-walled Tubes

Automotive radiator system lightweight is a key field of automotive lightweight.Compared with the traditional automobile radiator core,because the tube wall of the high-frequency welded tube is thinner and the inner diameter is larger,the contact area with the compressed hot air is larger,and the heat dissipation effect is better.Therefore,how to improve the weld quality and heat transfer efficiency of aluminum alloy thin-walled high-frequency welded pipes for automobile radiators was studied.In this paper,the heating process,welding defects and heat dissipation performance of high-frequency welding of aluminum alloy thin-walled tube are studied by combining numerical simulation and experiment.Firstly,the electromagnetic thermal coupling calculation of high-frequency welding was carried out by using the finite element software COMSOL.The distribution of temperature field in the heating process of high frequency welding is also studied.The results show that when the wall thickness is 0.26 mm and the frequency is 365 KHz,the induction heating is carried out on the whole wall thickness,and the temperature difference in the wall thickness direction is small,only about 4.5℃.The high temperature area of the pipe is mainly concentrated at the edge of the V-shaped corner,and approximately presents an X-shaped distribution in the direction of wall thickness.The maximum temperature of the pipe occurs at a small distance from the apex of the V-shaped Angle.Secondly,the influence of welding parameters(V-angle and welding frequency)and position parameters(concentricity of coil and welded pipe)on welding quality is analyzed.The results show that the higher welding frequency and the smaller V-angle can improve the heating efficiency,but the higher welding frequency will easily crack the welded pipe,and the smaller V-angle will lead to the formation of welding defects such as "sand hole".When other welding conditions are constant,the deviation of concentricity between coil and pipe will also change the heating efficiency.When the coil is lateral offset,the maximum temperature of the welded pipe changes with an average slope of 8.6℃/mm,and the temperature value of the welded pipe remains unchanged during the longitudinal offset.Finally,CFD method was used to study the effect of surface embossing method on heat dissipation performance of high frequency welded aluminum alloy tubes.The results show that both circular and keyway embossing can improve the heat dissipation performance of high frequency welded pipe welded pipes.The results show that both circular and keyway embossing can improve the heat dissipation performance of hf welded pipes.The heat dissipation efficiency of circular and keyway embossed welded tubes is increased by 10.7% and 2.8% respectively compared with that of non-embossed welded tubes,and the heat dissipation efficiency increases with the increase of fluid flow rate in the tube.