对某600 MW燃煤发电机组3根高调门螺栓和2根中调门螺栓(螺栓材料为R26合金)进行了化学成分分析、力学性能试验和金相检验。结果表明：5根螺栓材料化学成分均符合标准技术要求，其中3根高调门螺栓的硬度高于标准要求，且显微组织中存在标准中不允许出现的带状组织；2根中调门螺栓的力学性能满足标准要求，显微组织正常。螺栓中碳氮化物和金属间化合物呈带状分布会割裂基体，影响材料的高温持久强度，对设备的安全运行构成隐患。

Chemical composition analysis, mechanical property test and metallographic examination of three governor valve bolts and two intermediate pressure valve bolts of a 600 MW coal-fired power generating unit, were conducted. The results show that the chemical compositions of all the five bolts met the requirements of relevant standard, while the hardness of the three governor valve bolts was higher than the required value and there was banded structure which was not allowed in the microstructure. The mechanical properties of the two intermediate pressure valve bolts met the requirements of relevant standard, and the microstucture was normal. The carbon nitride and the intermetallic compound distributed in band in the bolts could cut apart the metal matrix, affect the high temperature creep rupture strength of the material and become a hidden danger to the safety operation of the unit.