火灾温度对紫铜焊接接头组织性能的影响

为了得到实际火灾现场中火焰和辐射热对电线及连接部位的电气损伤,模拟了不同温度对4mm厚的T3紫铜板焊接接头的作用,通过对焊接接头力学性能、电学性能和显微组织的分析,得出温度对紫铜焊接接头组织和性能的影响规律.结果表明,当火灾温度较低时,硬度会因退火强化而略有升高,当温度高于650℃时,硬度明显降低,火灾温度会对其造成严重性破坏;电阻率随温度变化影响不大;焊缝组织为粗大的α-Cu晶粒,内部有胞状晶亚结构生成,随火灾温度升高,晶粒长大,亚结构数量逐渐减少且分布弥散.

Effect of Fire Temperature on Microstructure and Properties of Copper Welded Joint

In order to obtain the effect of flames and radiant heat on the electrical injury of wires and connecting parts in actual fire scene,the effect of different temperatures on T3 copper welded joint with the thickness of 4 mm was simulated, through the mechanical and electronic properties of welded joints and microstructure analysis.The results show that the hardness is slightly higher due to annealing strength at low fire temperature when the temperature is higher than 650℃,the hardness significantly declines,which causes the serious damage.Electrical resistivity has few changes.The microstructure of the welded joint is coarse grains of α-Cu,crystal within the celluliform meta-structure generates.With the increase of temperature,the grain grows,the number of sub-substructure decreases and the sub-sffucture distributes diffusely.