为了研究加热温度和保温时间对铁铬铝电阻丝晶粒尺寸的影响, 利用一体化高温炉对电阻丝进行加热处理, 并用图像分析软件测定不同受热条件下电阻丝晶粒的平均截面积。结果表明: 在不同的加热温度和保温时间下, 电阻丝晶粒出现了不同程度的长大现象, 温度达到800 ℃左右时晶粒长大明显。对电阻丝晶粒尺寸的定量金相分析, 可以为火灾物证鉴定提供一定的参考依据。

For investigating the impact of heating temperature and holding time on crystal grain size of FeCrAl resistance wires, the resistance wires were heated by Muffle furnace. And the image analysis software was used to measure the mean sectional area of crystal grains on different heating conditions. The results show that the crystal grains of resistance wires grew in varying degrees with different heating temperature and holding time, and the growth degree of grains was obvious when the temperature reached at 800 ℃. The quantitative metallographic analysis on the grain size of resistance wires could provide some certain references for the identification of fire evidences.