某150MW塔式光热电站的熔盐管道发生开裂泄漏，通过宏观形貌观察、化学成分分析、拉伸性能试验、冲击性能试验、维氏硬度试验、金相分析、断口形貌分析、微区成分等方法分析了管道的开裂原因。结果表明：熔盐管道的失效模式属于热疲劳开裂，起源于角焊缝根部的管道外壁熔合区；在管道介质温度变化过程中，护板与管道间产生温差及轴向胀差，导致角焊缝根部由于角焊缝的约束引起的交变热应力作用下产生疲劳损伤，损伤累积到一定程度萌生裂纹、裂纹扩展至裂透熔盐泄漏。

The molten salt pipeline of a 150MW tower photothermal power plant cracked and leaked. The cracking reason of the pipeline was analyzed by means of macroscopic morphology observation, chemical composition analysis, tensile property test, impact property test, Vickers hardness test, metallographic analysis, fracture morphology analysis, micro-area composition and other methods. The results show that the failure mode of molten salt pipeline belongs to thermal fatigue cracking, which originates from the fusion zone of the outer wall of the pipeline at the root of the fillet weld; In the process of temperature change of pipeline medium, the temperature difference and axial expansion difference between the guard plate and the pipeline lead to fatigue damage at the root of the fillet weld due to the alternating thermal stress caused by the constraint of the fillet weld, and the damage accumulates to a certain extent to initiate cracks, and the cracks extend to crack penetration molten salt leakage.