300MW亚临界机组低温过热器泄漏失效分析

Analysis of Leakage Failure for Low Temperature Overheater in 300 MW Subcritical Unit

以某300 MW亚临界机组低温过热器泄漏管段为研究对象,采用金相检验、扫描电镜、硬度和拉伸性能测试等手段对低温过热器泄漏失效原因进行分析。结果表明:管子未出现明显力学性能老化,断面存在严重腐蚀,具有脆性断裂特征。对机组低温过热器泄漏管段显微组织和力学性能进行测试分析,通过观察其微观组织和力学性能变化,分析爆口损伤原因,提出运行监督建议,以期对低温过热器管氢腐蚀研究提供参考。

Taking the leakage tube section of the low temperature overheater in 300 MW subcritical unit,it analyzes leakage failure for the low temperature overheater by means of metallographic test,scanning electron microscope,hardness and tensile property tests.The results show that the tube does not appear obvious mechanical aging.The cross section has severe corrosion and brittle fracture characteristics.The microstructure and mechanical properties of the leakage pipe section of the unit low-temperature overheater are tested and analyzed,and the causes of burst damage are analyzed by observing the changes in its microstructure and mechanical properties.The operation supervision suggestions are put forward,in order to provide reference for the study of hydrogen corrosion of the low-temperature overheater tube.