steam turbines;  rotor;  Injuries;  Optimize startup

Aiming at the problem that the machine loss and fuel loss are large and prone to accidents when the steam turbine is started, the calculation of the thermal stress of the rotor is studied, and the calculation formula of the rotor thermal stress is derived. According to the continuous damage theory, the fatigue damage calculation of the rotor is discussed, and the optimization and starting problem of the steam turbine is discussed from the minimum total loss. The results show that the thermal stress at the start-up of the turbine is not as low as possible, but there is an optimal value, and the starting benefit is best around this value.