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本文采用交流电位法对处于高温条件下的汽轮机转子钢30Cr2MoV进行了第二阶段的亚临界疲劳裂纹扩展试验,并分别讨论了温度、应力比对裂纹扩展速率的影响,给出了高温状况下考虑两种介质(空气、蒸汽)时,冷、热态启动和负荷变化时的dα/dN与ΔK_I计算关系式,测定了350℃时的疲劳门槛值,为我国大型汽轮机带裂纹转子剩余寿命的估算及老机组的寿命管理提供了可靠的试验数据。
In this paper, the second stage of subcritical fatigue crack propagation of steam turbine rotor steel 30Cr2MoV under high temperature conditions was investigated by AC potential method. The influences of temperature and stress ratio on the crack growth rate were discussed respectively. The relationship between dα / dN and ΔK_I at two media (air and steam), cold and hot start and load change was calculated. The fatigue threshold at 350 ℃ was measured, which is the estimation of residual life of cracked rotor in large steam turbine in China And the life of the old unit management provides a reliable test data.