通过宏观检验、化学成分分析、力学性能测试、金相检验、断口扫描电镜分析等方法，对某锅炉末级再热器用TP310HCbN奥氏体耐热钢弯头泄漏原因进行了分析。结果表明：该弯头泄漏是因为其曾受到磕碰，破坏了钢管外表面的钝化膜；在腐蚀介质、管内压应力、弯管残余应力以及凹坑处附加内应力的共同作用下，弯头发生了应力腐蚀开裂。

The leakage causes of the TP310HCbN austenitic heat-resistant steel elbow of final reheater of a boiler were analyzed through macroscopic inspection, chemical composition analysis, mechanical property test, metallographic examination and fracture scanning electron microscope analysis. The results show that the elbow leaked because it had been bumped and the passivation film on the outer surface of the steel tube was damaged. Under the combined action of corrosive media, tube internal compressive stress, residual stress of the elbow and additional internal stress at the pit, stress corrosion cracking occurred to the elbow.