镍钛合金医疗器械产品里的镍钛丝在生产过程中发生断裂，采用化学成分分析、力学性能试验、洁净度测试、宏观分析、显微硬度测试和断口微观分析等方法对镍钛丝的断裂原因进行了分析。结果表明：在镍钛丝的编织加工过程中，丝材穿过固定钢套的弯曲区域时，加工硬化应力消除不够彻底，导致镍钛丝在承受较大的弯曲应力时，发生过载塑性断裂。

The nitinol wires in a nickel titanium alloy medical device product fractured during production. The fracture reasons of the nitinol wires were analyzed by chemical composition analysis, mechanical property test, cleanliness test, macro analysis, micro hardness test and micro analysis of fracture surface and so on. The results show that when the wires passed through the bending area of the fixed steel sleeve during the braiding process of the nitinol wires, the work hardening stress was not completely eliminated, which resulted in overload plastic fracture of the nitinol wires under large bending stress.