【摘要】 对 LY1 0、TB2 - 1和 NSA5 41 5等三种铆钉材料在不同加载速率下的变形进行微观研究 ,结果表明采用电磁铆接这种冲击加载 ,铆钉镦头会出现应变集中带或绝热剪切带。散热性能较差的TB2 - 1铆钉对应变率较敏感 ,铆接时镦头中将出现绝热剪切带。随着加载速率的提高 ,绝热剪切带中的变形量愈来愈大 ,最终出现微裂纹或剪切破坏。为保证电磁铆接的质量 ,应选择合适的加载速率。现有电磁铆接设备的加载速率偏高 ,不适合 TB2 - 1等铆钉材料的铆接 ,应增大其电容量 ,以降低加载速率。为扩大电磁铆接设备的适用范围 ,使其电容量可调 ,以满足不同材料对加载速率的要求。更多还原

【Abstract】 Aiming at improving the quality of electro magnetic riveting(EMR), and eliminating cracks in rivet heads, we studied the deformation of some rivet materials in different loading rate by microcosmic analysis. Fig.1 gives the schematical diagram of EMR. By adjusting the capacitance of the riveter, we carried out riveting experiments at three different loading rate for three kinds of rivet materials. Table 1 gives the parameters of experiments, Figs.2 through 4 illustrate metallographs of three rivet heads at different loading rate. We get the following conclusions by analyzing these figures: (1) The loading rate of EMR has great influence on the deformation of rivet materials. (2) The materials riveted by EMR undergo adiabatic shear forming, microcracks will appear if the loading rate is too high. (3) The reason that cracks appear in TB 2 1 rivet heads is that the loading rate of existing high voltage electro magnetic riveter is too high, their capacitance should be increased to lower their loading rate.更多还原