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对运行16年的30Cr1Mo1V亚临界汽轮机高中压转子进行解剖试验,采用直流电位法对材料在538℃下的蠕变裂纹、蠕变-疲劳裂纹萌生与扩展行为进行了研究,分析了不同初始应力强度因子对蠕变裂纹扩展孕育时间和蠕变裂纹扩展速率的影响,并对高温段和低温段的相关性能进行了比较,研究了不同保持时间对蠕变-疲劳裂纹扩展行为的影响,同时还分析了不同条件下裂纹扩展行为的时间或循环相关性.结果表明:疲劳缩短了蠕变-疲劳裂纹的扩展孕育期,加速了裂纹的扩展;载荷保持时间较短情况下,蠕变-疲劳裂纹扩展行为与循环相关;载荷保持时间较长情况下,裂纹扩展行为与时间相关.
The 16-year-old 30Cr1Mo1V sub-critical turbine high and medium pressure rotors were subjected to anatomical tests. The creep cracks and creep-fatigue crack initiation and propagation at 538 ℃ were investigated by DC potentiometry. The effects of different initial stress intensities The influence of different retention time on the creep-fatigue crack growth behavior was also studied. The influence of different retention time on creep-fatigue crack propagation was also studied The results show that: the fatigue shortens the expanding period of creep-fatigue crack and accelerates the propagation of the crack; the creep-fatigue crack growth in the short time of the load holding time Behavior is related to circulation; crack extension behavior is time-dependent with longer load holding time.