某超超临界1 000 MW机组高温再热器入口集箱刚性吊架螺纹吊杆发生断裂，采用宏观观察、化学成分分析、硬度测试、室温拉伸性能测试、金相检验、断口分析等方法对其断裂原因进行分析。结果表明：螺纹吊杆断面附近存在明显颈缩现象，整个断面上均存在蠕变孔洞，蠕变孔洞长大、聚集并形成蠕变裂纹；炉顶大包内实测温度大幅超过了原设计值，在实测温度下轴向应力计算值超标，在高温和高应力作用下，在应力集中的牙根部位发生蠕变断裂。

Rigid hanger thread suspender of high temperature reheater influent header of an ultra supercritical 1 000 MW unit fractured. The fracture reasons were analyzed by macroscopic observation, chemical composition analysis, hardness test, room temperature tensile performance test, metallographic examination and fracture surface analysis. The results show that there was obvious necking phenomenon near the section of the threaded suspender, and there were creep holes on the whole section. The creep holes grew, aggregated and formed creep cracks. The measured temperature in the ladle on the top of the furnace greatly exceeded the original design value, and the calculated value of axial stress exceeded the standard under the measured temperature. Under the action of high temperature and high stress, creep fracture occurred at tooth root with stress concentration.