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随着电气化的普及,因电气线路短路、过负荷以及电气装置工作异常等因素导致的火灾逐年增多。利用电焊机模拟火灾前电气设备出现短路制备一次短路熔珠;通过酒精喷灯提供热量,模拟二次短路熔珠的形成环境。利用扫描电子显微镜,观察和分析铝导线熔珠内部孔洞的微观形貌,发现铝导线一、二次短路熔珠内部空洞的微观形貌具有显著区别,前者孔洞所占面积较小,形状比较规则,内部孔洞内壁呈胞状晶、柱状晶,较为光滑;后者孔洞面积较大,孔洞数量明显增多,孔洞内壁杂质多且粗糙,有较多裂纹分布。利用内部孔洞微观形貌的区别可以鉴别铝导线熔珠形成的原因。
With the popularization of electrification, the fire caused by factors such as short circuit of the electric circuit, overload and abnormal work of the electric device increases year by year. The use of welding machine to simulate the electrical equipment before the fire short circuit to prepare a short bead; through the alcohol torch to provide heat to simulate the formation of secondary short-circuit the formation of molten beads. Scanning electron microscope (SEM) was used to observe and analyze the micro-morphology of the holes in the aluminum wire. It was found that there was a significant difference between the micro-morphology of the first and second short-circuit molten aluminum beads in the aluminum wire. The former occupied a smaller area and the shape was more regular , The inner wall of the inner hole was cellular crystal, columnar crystal, more smooth; the latter hole area larger, the number of holes increased significantly, the inner wall of the hole more impurities and rough, more cracks. The reason for the formation of molten aluminum beads can be identified by the difference of the micro-morphology of the internal pores.