某热电联产机组波纹膨胀节裂纹分析

Crack Analysis of Corrugation Expansion Joint of A Cogeneration Unit

某电厂600 MW抽气型热电联产机组波纹膨胀节在运行约10 000 h后,低压导气管波纹膨胀节第一节工作波发生波纹管破裂。文章通过对波纹管的奥氏体不锈钢材料性能、组织结构、断口形貌以及机组振动等方面予以分析,发现波纹管为疲劳裂纹扩展破裂失效。导气管振动是引起波纹管发生失效破裂的主要原因,其次波纹管的材料冷作硬化是波纹管局部破口的直接原因。通过对波纹管破裂的机制和原因分析,从而为该型机组波纹管的寿命延长提了出有益的改进措施。

After a 600 MW extraction type cogeneration unit running 10 000 h, the first quarter wave of low pressure corrugated tube has occurred fracture accidents. This article analyzes material performance, organizational structure, fracture morphology for the corrugated of austenitic stainless steel, as well as the vibration test, experiments demonstrate that corrugated pipe crack results from Ω- peak as fatigue crack initiation. Vibration is one of the main cause of the fatigue, the immediate cause is material cold work hardening of the corrugated pipe. By analyzing the fatigue mechanism, improvement measures are putted forward for promoting the life of corrugated pipe.