过电流故障诱发铜导线喷溅熔珠的特征

The Characteristics of Spattered Beads Generated by Overcurrent Fault of Copper Wire

过电流故障是一种常发电气故障,具有很高的火灾危险性。利用电气火灾故障模拟及痕迹制备装置制备不同过电流值故障下单芯铜导线熔断产生的喷溅熔珠,借助金相分析技术分析讨论了电流值对熔珠组织特征的影响。结果显示:电流值的升高会使喷溅熔珠产生的数量大致呈现下降趋势,电流值为136 A时产生的喷溅熔珠平均数量最多,为4.8个。根据金相组织特征形貌的不同,喷溅熔珠金相组织可分为9类:树枝晶规则孔洞,树枝晶不规则孔洞,树枝晶无孔洞,等轴晶规则孔洞,等轴晶不规则孔洞,等轴晶无孔洞,混合晶规则孔洞,混合晶不规则孔洞,混合晶无孔洞。在所有喷溅熔珠中,树枝晶不规则孔洞金相组织出现的次数最多。

Overcurrent fault is a frequently electrical malfunction with high fire hazard.In this paper,spattered beads were prepared using an electrical fire fault simulation device with fusing single-core copper wire under different overcurrent faults,and the effect of current value on the organizational characteristics of the beads was analyzed and discussed with the aid of metallographic analysis.The results show that:the increase of current value will cause the number of spattered beads to decline roughly;when the current value is 136 A,the average number of spattered beads generated reaches is 4.8,the biggest number.According to the different characteristics of the metallographic organization,the metallographic organization of sputtering beads can be divided into nine categories:dendrite with regular holes,dendrite with irregular holes,dendrite with no holes,equiaxial crystal with regular holes,equiaxial crystal with irregular holes,equiaxial crystal with no holes,mixed crystal with regular holes,mixed crystal with irregular holes and mixed crystal with no holes.Of all spattered beads,metallographic organization displaying dendrite with irregular holes appears most often.