Study On The Deformation Mechanism And The Technological Parameter Of The Low Voltage Electromagnetic Riveting

Riveting is a kind of connection technique which can not be disassembled during service period. Compared with other connection process, it has many advantages, such as simple technics, reliable connection strength, low cost and adapting to connect various kinds of materials etc. By means of increasing the capacitance and decreasing the voltage, we control the discharging energy and apply the low-voltage electromagnetic riveting (LVER) process to rivets made of some widely used materials. This results in the decrease of complexity and volume of the equipments and the notable decline of the production costs. At the same time, the life-span and the operation security of the whole system are guaranteed.After a detailed analysis of the situation of the electromagnetic forming and electromagnetic riveting domestically and overseas, basing on the method of combining academic analysis with experiment research, we systematically studied the technological parameter and deformation characteristic of the rivets. The riveting quality is analyzed and tested at last.Based on the partial alteration of ready-made electromagnetic forming equipments of our own, all the experiments to different material rivets are carried out successfully. The idea deforming voltage range for materials L4, LC3, 10 and Q235 are 450V-500V, 550V-600V and around 900V respectively. It is followed by a systematically analysis of the effect brought by the change of discharge parameters such as the voltage and the capacitance on deforming force and final riveting quality. Along with the increase of voltage and capacitance, the magnetic pressure P value increases and is in direct ratio with square that of V. Afterwards, the deformation mechanism of the rivets in microcosmic world is analyzed with the help of phase experiment. The shear zone in rivets becomes more and more obvious when the strength of material increases. Although different material presents different deforming characteristic, no crack is found due to the relative low load speed rate. This has proved the feasibility of the LVER process for rivets made of material with high strength and sensitive to strain ratio and its broad serviceable range. TheLVER process has the character of high deforming efficiency and low interference value, so it is favorable for the riveting of composite, too.At last, the tensile-strength and the shear strength of obtained products are tested and measures which can improve the quality of the riveting are provided. The method for how to attain qualified products is provided. The assay indicates that the tensile-strength and the shear strength of rivet connection obtained from LVER process is equivalent to that of bolt connection but is obviously better than that of rivet connection obtained from general hammered riveting process.