对一支保护管为GH3128高温合金的铠装热电偶电缆的断裂原因进行分析,并提出工艺改进措施。结果表明:保护管内壁存在凹坑,并有氧化镁嵌入,使内壁在拉拔过程中受到较大应力,增加了裂纹源萌生的概率;铠装电缆保护管内、外壁受到较大应力,使其材料发生成分偏析,材料显微组织极不均匀,最终导致铠装电缆在弯曲加工过程中断裂。

The fracture reason of a armored thermocouple cable with GH3128 superalloy protection tube was analyzed, and the process improvement measures were proposed. The results show that there were pits in the inner wall of the protection pipe, and magnesium oxide was embedded, so that the inner wall was subjected to greater stress during the drawing process, which increased the probability of crack initiation. The inner and outer walls of the protective tube of armored cable were subjected to large stress, which caused the material to segregate, and the microstructure of the material was extremely uneven, and finally led to the fracture of armored cable in the bending process.