着床后引燃对电弧迸溅熔珠组织特征的影响

Influence of ignition after landing on microstructure characteristics of arc splashed melted bead

为探究迸溅熔珠着床后的热交换过程对其组织特征的影响,建立基于着床后高温迸溅熔珠的动态测温方法,从而揭示迸溅熔珠着床后引燃与否对其组织特征形成的影响规律。研究结果表明:引燃可燃物的熔珠受火焰热反馈和铜氧化放热的共同作用,着床后其温度出现反复波动,延长迸溅熔珠的冷却凝固时间,组织呈等轴状;无法引燃可燃物的熔珠在可测范围内,短暂升温后降温速率持续上升,组织更易呈现树枝状或胞状。研究结果可为准确认定电气故障电弧迸溅熔珠引发火灾提供技术支持。

In order to explore the influence of heat exchange process on the microstructure characteristics of the splashed melted bead after landing,a dynamic temperature measurement method for the high-temperature splashed melted bead after landing was established,and the influence of ignition on the formation of microstructure characteristics of splashed melted bead after landing was revealed.The results showed that under the combined effect of flame heat feedback and copper oxidation heat release,the temperature of melted bead igniting the combustibles fluctuated repeatedly after landing,which prolonged the cooling and solidification time of the melted bead,with the equiaxed microstructure.Within the measurable range,the cooling rate of the melted bead without igniting the combustibles continued to increase after a short period of temperature rise,and its microstructure was more likely to appear the dendritic or cellular structure.The results can provide technical support for accurately identifying the fire caused by the splashed melted bead of electrical arc fault.