The combined rotor of gas turbine bears large centrifugal stress and high temperature in a long term,and its performance degrads easily.Turbine discs creep is one of the important fac-tors that cause the performance degradation of the combined rotor.To research the performance degradation characteristics of combined rotor caused by turbine discs creep,firstly,the turbine discs creep calculation model of combined rotor considering contact interface stiffness was estab-lished,the creep effect and the relationship between creep quantitative data and time were re-searched.Then a research method for the performance degradation of the combined rotor caused by turbine discs creep was presented.By describing degradation path caused by turbine discs creep through defining degradation degree parameters,performance degradation quantitative eval-uation of combined rotor was realized.Finally,the variation law of the performance degradation rate of the combined rotor was studied under the different speeds and numbers of rod.The calcu-lation results showed that the creep rate of combined rotor decreased with the increasing of time, and the first wheel of the turbine got the fastest creep rate;the turbine discs creep caused per-formance degradation of combined rotor,the greater the rotating speed,the more number of the rod,the faster the degradation rate of the combined rotor.Therefore,it is necessary to consider the influence of turbine discs creep on the structural design of composite rotor,especially when the speed and the number of the rod are changed,the influence can not be ignored.%燃气轮机组合转子因长期承受较大的离心应力及较高的温度，其性能易发生退化。轮盘蠕变是引起组合转子性能退化的重要因素之一，为研究轮盘蠕变引起的组合转子性能退化特性，首先建立了考虑轮盘结合面刚度的组合转子轮盘蠕变计算模型，研究组合转子蠕变效应，得到组合转子不同轮盘蠕变随时间变化的定量数据；然后，提出了轮盘蠕变引起组合转子性能退化的研究方法，通过定义组合转子性能退化指标，得到轮盘蠕变引起组合转子性能退化的轨迹，实现其性能退化的定量评估；最后，研究不同转速、拉杆数目下轮盘蠕变引起组合转子性能退化速率的变化规律。结果表明：在高温、高转速作用下，组合转子轮盘将会发生蠕变，透平端第1级蠕变速率最快；轮盘蠕变会引起组合转子性能退化，转速越大、拉杆数目越多，组合转子退化速率越快。因此，在对组合转子进行结构及系列化设计时必须考虑轮盘蠕变的影响，特别在改变转速、拉杆数目时，其影响不容忽视。
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