火灾场景对电气火灾熔痕微观尺度特征的影响

The Effect of Fire Environment on the Micro-scale Features of the Electrical Fire Melted Mark

为研究火场温度和火场持续时间下所形成的火灾熔痕的微观尺度参数的变化规律,本文通过进行模拟火灾场景从而重现火灾环境,进而采用XRD分析模拟的熔痕,分析熔痕的晶粒大小和微观应变等微观结构和尺度特性参数。结果显示:(1)微观应变和晶粒大小随火场持续时间变化存在一定的变化规律:随火场持续时间增大,微观应变先增大后减少,而晶粒大小的变化规律大致呈倒U型趋势。而随火场温度变化基本呈不断波动的变化趋势,相关度不高;(2)熔痕晶面(111)和(200)的晶粒大小和微观应变随火场持续时间变化规律在200A和300A电流短路情况下较为一致,而与400A电流短路情况下不一致。研究表明,火场温度和火场持续时间对熔痕围观尺度的特征有规律性影响,可初步形成不同熔痕围观尺度特征参数对应不同火场环境的相互关系体系。

In order to research micro-scale parameter of melted mark under the different fire temperature and duration of the fire. In this article, the primary short circuited melted mark and secondary short circuited melted mark are simulated in the different fire environment, Short circuited melted marks are grinded, polished and cleaned, so as to the microstructure of melted marks are tested by X-ray diffracto-meter. Experimental results indicate that there are certain rules between micro-strain （ and grain size） and duration of fire：with the increase of duration of fire, the micro strain increase and then decline, and the grain size roughly showed an inverted U-shaped trend, but the grain size and micro strain did not show clear relation with the temperature of fire. Meanwhile, the grain size and micro-strain on （ 111） and （200） planes of Cu showed the similar trend with the increase of duration of fire between 200A and 300A,but the data of 400A was different and opposite. there was relation between the grain size and micro strain of melted mark and temperature and duration of fire, it could set up a system about the relation between micro-scale features of the electrical fire melted mark and fire environment, to satisfy the requirements of the quantitative analysis in electrical fire material evidence identification.