As the constant commissioning and operation of large-capacity high-parameter units

the creep problem of turbine rotor at high temperature is becoming more and more severe.However

research on creep characteristic of high temperature material in China is still at the primary stage. The multidimensional stress creep constitutive equation and the Norton three-parameter model was applied to describe the creep characteristic of the high/intermediate pressure rotor in a supercritical 660MW unit

and the style of piecewise fitting was adopted to determine the three parameters of the Norton model.The calculation results show that

the creep mainly occurred on shaft between the rotor steam seal and the third stage dynamic blade in medium pressure cylinder;due to the creep

after 10 500hours' operation

the rotor would bend gradually

and the bend rate will be increasing

especially that at the steam seal in middle rotor reached the highest value.The calculation agreed well with the measured results.