某电厂超超临界锅炉一级过热器T91钢吊挂管在运行1 400 h后发生泄漏。通过宏观检查、化学成分分析、力学性能试验、硬度测试和金相检验等方法对吊挂管泄漏原因进行了分析。结果表明：吊挂管发生短时过热，其耐压强度急剧下降，在内部介质压力作用下，管段发生胀粗和壁厚减薄，当壁厚不足以抵抗内压作用时管段发生爆裂，导致该吊挂管的泄漏。

The T91 steel supporting tube of primary superheater of ultra supercritical boiler in a power plant leaked after operating for 1 400 h. By means of macroscopic examination, chemical composition analysis, mechanical property test, hardness test and metallographic examination, the causes of leakage of supporting tube were analyzed. The results show that the pressure strength of the supporting tube decreased sharply due to its short-time overheating. Under the internal medium pressure, the tube section expanded and the wall thickness decreased. When the wall thickness was not enough to resist the internal pressure, the tube section bursted, resulted in the leakage of the supporting tube.