电气短路火灾中火场温度环境对多股铜导线金相组织的影响

Effect of temperature environment on metallographic structure of multi-strand copper wire in electrical short circuit fire

以横截面积为2.0 mm^(2)的多股铜导线为原材料,结合电气发生的一次和二次两种短路故障,制备一次短路熔珠和二次短路熔珠,并以此基础制备对应的温度环境试样和热时间试样。通过高温拉伸测试、金相组织定量分析,研究电气短路火灾中火场温度环境对多股铜导线金相组织的影响。试验结果表明:多股铜导线的拉伸位移和断面收缩率在高温环境下显著降低,高温时间的增加会使两种短路熔珠发生组织变化,但对一次短路熔珠热时间试样的影响较小。两种短路熔珠的温度环境试样晶粒均随着温度的增加而增大,且晶粒显著的方向性特点逐渐消失。温度对于一次短路熔珠的影响较大,时间的增加对其的影响相对较小,二次短路熔珠会受到温度变化和高温持续时间长短的双重影响。

The primary and secondary short-circuit beads were prepared by using the cross-sectional area of 2.0 mm^(2) and multi strand copper wires as raw materials.The primary and secondary short circuit beads were prepared.Based on this,the corresponding temperature environment samples and hot time samples were prepared.Through high temperature tensile test and quantitative analysis of gold phase structure,the influence of fire field temperature environment on the metallographic structure of multi-strand copper wire in electrical short circuit fire is studied.The results showed that the tensile displacement and section shrinkage of the multi strand copper wire decreased significantly in high temperature environment,and the increased of high temperature time would cause the structure change of the two kinds of short-circuit beads,but the influence on the primary short-circuit bead hot time sample was small.The grains of the two kinds of short-circuit beads enlarge with the increase of temperature,and the obvious directionality of the grains gradually disappeared.The temperature had a great influence on the primary short circuit bead,and the increase of time had a relatively small influence on it.The secondary short circuit bead would be affected by the temperature changes and the duration of high temperature.