| The welded parts of aluminum alloy and ferroalloy have significant advantages in key performance parameters such as strength,weight and corrosion resistance,and have broad application prospects in aerospace and automobile manufacturing industries.However,the physical properties of the resistivity,thermal conductivity,specific heat capacity,and melting point of the two types of alloys are quite different,and the solid solubility between the two alloys is relatively low,and it is easy to form a brittle reaction layer at the interface,and difficult to achieve good welding of aluminum alloy and iron alloy by the traditional welding method of fusion welding.Aiming at this problem,this paper has carried out research on welding method based on electromagnetic pulse technology.In view of the shortcomings of existing electromagnetic pulse welding technology in the welding of dissimilar materials metal plates,two types of electromagnetic pulse welding methods based on field shaper and background magnetic field are proposed,which improves the collision speed of the workpiece and the welding quality by the same mechanism and different implementation schemes.On this basis,the system carried out the mathematical analysis model,electromagnetic-structure optimization design method,device development and experimental research of two types of welding systems.Firstly,the model and parameter analysis of the plate electromagnetic pulse welding based on the field shaper are carried out.Based on the principle of electromagnetic pulse welding with field shaper,the equivalent circuit model of filed shaper based on current wire method is constructed,and the optimal design of shape parameters and coil turns of the field shaper is realized efficiently.On this basis,a 2D sequential coupled finite element model based on COMSOL and a 3D electromagnetic field and structural field loosely coupled finite element model based on ANSYS are constructed.Among them,this part is based on the 2D finite element model to analyze the energy distribution in the electromagnetic pulse welding process in detail,and obtain the energy conversion efficiency and other parameters of the electromagnetic pulse welding energy.At the same time,the common problems in the electromagnetic pulse welding such as the influence of circuit parameters on the collision speed of the workpiece are analyzed.It is pointed out that decreasing the inductance of the line and increasing the capacitance voltage is an effective method to improve the collision speed in the electromagnetic pulse process.Secondly,the development and experimental research of electromagnetic pulse welding device based on field shaper are carried out.The 3D finite element model was used to design the electromagnetic pulse welding device based on the field shaper and the key components.The effectiveness and reliability of the welding method and device were demonstrated by a series of experiments.Based on the finite element model,the magnetic field and electromagnetic force distribution characteristics of the workpiece area under the action of the field shaper and the plastic deformation behavior of the workpiece during the welding process are analyzed in detail.And the formation process and temperature change process of welding interface of different interfaces during the welding process are analyzed microscopically.On this basis,the welding experiment platform was built and the welding experiments of 1mm thick 1060 aluminum plate and 304 stainless steel plate were carried out with different pore size field shapers.Based on the analysis of the appearance,section and microstructure of the welded samples,related process experiments were carried out.The results of the process test show that the method can better complete the electromagnetic pulse welding of aluminum plate and stainless steel plate.Finally,the electromagnetic pulse welding method,device development and experimental research based on background magnetic field are carried out.The electromagnetic-structure finite element model of the welding system is constructed.The background magnetic field coil is optimized.The proportional relationship between the number of coil layers and the number of turns is obtained,and the reinforcement scheme is determined.The influence of the key electromagnetic parameters(eddy current,electromagnetic force,etc.)of the workpiece and the plastic deformation behavior of the workpiece during the background magnetic field welding process are explored.On this basis,the welding experiment was carried out with 1mm thick 1060 aluminum plate welding,and the appearance,the macroscopic analysis of the section and the microscopic analysis of the welding interface were carried out.At the same time,the tensile strength and hardness of the welded sample were tested.The experimental results show that the method can effectively improve the collision speed and improve the welding quality. |
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