Study On Flanging Process And Designing Prefabricated Hole Of AA5052 Alloy Tube By Electromagnetic Forming

T-tube was widely used in automobile,aerospace and other industries to achieve oil diversion,buffer flow rate and other functions.Aluminum alloy T-tube can effectively reduce dead weight and realize lightweight production of parts.However,the poor formability of the material at room temperature,high cost of traditional process,complex equipment and low production efficiency have been restricting its wide application.As a typical high-rate forming technology,the electromagnetic forming has the advantages such as improving the plastic deformation ability of materials,simple die structure,good surface precision of parts and high processing efficiency.In this paper,AA5052-O aluminum alloy pipe was the research object,to explore the application of electromagnetic pulse pipe flanging process in the forming of aluminum alloy three-way pipe.Firstly,the design method of flanged prefabricated holes was put forward.and the calculation formula of prefabricated holes was obtained based on the invariant assumption of plain line by using the method of drawing analysis.And two kinds of prefabricated holes,drum shape and ellipse shape,were designed.Simplified processing of dies,then,the electromagnetic flanging simulation model of aluminum alloy pipe fitting was established by LS-DYNA software,and the general rule of electromagnetic flanging was acquired.By comparing the flanging results of two kinds of prefabricated holes,an elliptical prefabricated hole with flat branch pipe ports and low thinning rate was determined and verified by experiments.Then,several groups of simulation were designed based on the elliptical precast hole.Aiming at the different requirements of branch pipe height and thinning rate,the selection window of precast hole parameters was obtained,and the calculation formula of prefabricated hole was modified.The test results displayed that the maximum thinning rate of the branch pipe was 15.8% and the height deviation was only 3.56%,which confirmed the correctness of the window and calculation formula.At the same time,the hardness test of the test samples revealed that the material at the end of the branch pipe of the long shaft occurred large deformation,which was most affected by the deformation and hardening.Finally,a new electromagnetic flanging inductor was proposed to address the problem of the traditional spiral coil sensor being easy failure.The optimal structural parameters of the new inductor were obtained by means of numerical simulation and experiment.The calculation formula of prefabricated hole was modified for the new inductor,and a matching window for selecting the parameters of prefabricated hole was established.The results illustrated that the maximum thinning rate of branch pipe was 15% and the height deviation was only 2.5%.