Research On Technologies Of Tube Magnetic Pulse Flanging

Multi-pass tube is a kind of typical pipe which is mainly used in petroleum, aviation, aerospace, weapons, production and life for transporting the pipeline fluid. Forming a regular Multi-pass tube commonly used casting, welding, Tube hydroforming and the press flanging, resulting for problems such as rough tube wall, poor corrosion resistance of welding, complex machining process, lower flanging height and so on. Forming multi-pass tube by magnetic pulse flanging, because of the advantanges such as high precision furface, the overall shape without welding, simple and efficient process, higher limit flanging height, it have broad application prospect in the production. So research on the tecnologies of tube flanging has inmportant significance. Based on the accurate calculation of tube side preformed hole size, combinating the numerical simulation and the magnetic pulse flanging experiment to explore the main process parameters on deformation.First, by drawing with analytical and MATLAB software, the tube defromation process is abstracted as mathematical problems, establish the mathematical model for the analysis and programming to solve, finally get two shapes of preformed hole: oval-shaped and double-drum, establish the finite element model as this and process of pre-tube,then experiment verification.Based on ANSYS finite element simulation software,using edge element method to establish the FE model of tube electromagnetic flanging for solving three-dimensional electromagnetic fields. the results show that the wall of tube opening and the magnetic leakage occurred, the magnetic force reach max value near the major axis port of voal hole. The magnetic force near the minor axis port of voal is relatively small, the greater stress the closer port. Test results and simulation results are consistent, the area near long axis of the port reach large amount of metal deformation because of high magnetic force. thinning trend in the region seriously, are necking danger zone. As a basis for the long axis of the port to take on the pre-grinding holes rounded, polished smooth and other measures to effectively curb thinning.Take the flanging experiment, voltage, the results show that the voltage increases, the beneficial tube punch. High frequency discharge will result in the acceleration of tube deformation too large, high-speed crash dies and breaks down, low-frequency discharge can cause the skin depth increase, the reversed magnetic repulsion will stop punching. Compared with the short coil, long coil will increase non-uniformity to punch the wall, and also need higher discharge energy; best shape of pre-hole is approximate oval. Take experience in the discharge capacitor of 4×192μF and voltage of 4500V, the long/short axis is 38.72/16.24 mm and 18.72/10.11 mm, flange diameter isΦ50 mm and flange diameter isΦ30mm, can get flush port tube,flange height can reach 6 mm, compared to the traditional flanging can increase the limit of 24.7%. Thinning of the holes is in long axis of pre-tube, the maximum thinning capacity is 50%, proper lubrication can effectively inhibit the thinning and deformation inhomogeneity. At last, summary the optimum route of trials and production.