Low Cycle Fatigue Crack Growth Behavior of Modified Rotor Steel under High-Temperature

AbstractMany components in power plants are subjected to low cycle loading under high-temperature during continuing service. Therefore, creep-fatigue damage has been become a significant concern in the design and operation of these components. This damage mechanism initiates cracks at critical locations and subsequently creates a potential risk to safe and reliable operation. Creep-fatigue crack growth rate data are necessary inputs for assessing the structural integrity of high temperature components in power plants. Creep-fatigue crack growth tests were conducted for a modified X12Cr rotor steel at 600°C under trapezoidal wave shape load amplitude conditions with various hold times using C(T) specimens. A direct current electrical potential-drop was used to monitor crack growth length during the tests.It is shown that crack growth behavior under creep-fatigue conditions is characterized better by the (Ct)avg parameter, and the formula of assessment low cycle fatigue crack growth under high-temperature was fitted by use of ΔK and (Ct)avg parameter