Study On Magnetic Pulse Welding (MPW) Method For Aluminum To Steel Sheets Metal Joints Of Autobody

The application of aluminum and magnesium and other lightweight alloys in the car body is an effective vehicle for lightweight means.There are many limitations of traditional welding technology when dealing with the connection of aluminum and other metals,and its limits the use of aluminum in the body.Magnetic pulse welding technology is a solid-phase welding technology.It can avoid the heat affected zone and achieve high-quality weld.It is very suitable for solving the problem of dissimilar metal welding.In this paper,the magnetic pulse process of 5182 aluminum plate and HC340LA steel plate is studied by numerical simulation,process test,weld mechanical property test and microscopic analysis of welding interface.The main contents of this paper are as follows:Firstly,baseed on the FEM(Finite Element Method)and BEM(Boundary Element Method),A numerical simulation model of multi-field coupling is established to predict the magnetic pulse welding process of time-varying current,electromagnetic force and plate deformation process.And the influence of the discharge energy,spacing and other important parameters on magnetic pulse welding process is explored to guide the magnetic pulse welding process test.The results indicate that the higher diacharge energy leads to higher impact velocity,However,the increament of the standoff gap results in the increament both of the impact velocity and impact angle.Secondly,the magnetic pulse welding process test is completed with appropriate process parameters.The acceleration process of the flyer and collision speed with different process parameters during the mageneitc pulse welding process are obtained by Photonic Doppler velocimeter(PDV)system.The mechanical properties of magnetic pulse welding are determined by shear test.The results show that the appropriate welding parameters can achieve high quality welds beyond the base metal strength.On this basis,the effects of different discharge parameters on the strength of the magnetic pulse weld are investigated,and the appropriate discharge process parameter window is established.A comprehensive analysis is completed by a variety of micro-analysis methods including the magnetic pulse welding interface morphology,element diffusion,transition zone organization and micro-defects.Meanwhile,the influence of energy and spacing on microcosmic characteristics is analyzed.The results show that the suitable process parameters can obtain good waveform interface and long welding area.Some intermediate layer forms in the rough of the waves.What’s more,oversaturated Al-Fe solid solution is found in the intermediate layer.