Recently, there is the serious fracture for two high-temperature steam turbine rotors made of 30Cr1Mo1V steel in different power plants, characterized by brittle fracture. This steel has the disadvantage of low temperature brittleness. Currently, a large number of 30Cr1Mo1V rotors are in service. Meanwhile, these rotors are required to start up and warm up faster due to the demand for operation flexibility of the power system. In order to ensure the safety of the 30Cr1Mo1V rotors under flexible operation, it is necessary to study the low temperature brittleness of the rotors and its influence on the fatigue life in rapid start-up and warm-up processes. In this paper, the fracture causes of the 30Cr1Mo1V rotor were analyzed by the mechanical property tests, microstructure examination and fracture analysis. The test results showed that the toughness of rotor decreased significantly after service. Secondly, the temperature and stress changes of the high-temperature rotors during the rapid start-up and warm-up process were calculated by the finite element method. The simulation results showed that if the speed rose too fast, the thermal stress in the rotor inlet area would increase significantly and the temperature was lower than the fracture appearance transition temperature when reaching the full speed. The high stress will easily lead to a crack initiation under low-cycle fatigue. Then, crack instability propagation will soon occur due to the low temperature and poor toughness. Thirdly, the life of the turbine in the rapid start-up was optimized by controlling the startup time. In addition, the life under different warm-up conditions was quantitatively analyzed. It not only reveals the necessity of the warm-up process for the center hole rotor, but also successfully demonstrates that the warm-up process of the solid rotor can be cancelled, which improves the economy of the power plant.

近期，不同电厂的两台30Cr1Mo1V钢高温汽轮机转子发生严重断裂，表现为脆性断裂。这种钢具有低温脆性的缺点。目前，大量的30Cr1Mo1V转子在服役。同时，由于对电力系统运行灵活性的要求，这些转子需要更快地启动和预热。为保证30Cr1Mo1V转子在灵活运行下的安全性，有必要研究转子在快速启动和预热过程中的低温脆性及其对疲劳寿命的影响。本文通过力学性能测试、显微组织检查和断裂分析，对30Cr1Mo1V转子的断裂原因进行了分析。试验结果表明，转子在使用后韧性明显下降。其次，采用有限元方法计算了高温转子在快速启动和预热过程中的温度和应力变化。仿真结果表明，如果转速上升过快，转子入口区域的热应力会显着增加，达到全速时温度低于断裂出现转变温度。在低周疲劳下，高应力容易导致裂纹萌生。然后，由于低温和韧性差，裂纹不稳定扩展很快就会发生。第三，通过控制启动时间，优化快速启动时的汽轮机寿命。此外，定量分析了不同预热条件下的寿命。不仅揭示了中心孔转子预热过程的必要性，而且成功地证明了可以取消实心转子的预热过程，提高了电厂的经济性。