Theses and Dissertations Collection

High chromium heat resistant steels are commonly used for boiler components that are operated around 600ºC in ultra-supercritical (USC) thermal power plants. This study focuses on the creep fatigue crack growth, creep crack growth and creep brittle or ductile behavior of ASME P92 steel at 650ºC. All specimens were machined from a header pipe in a homogeneous fashion. A side groove analysis was performed to determine the best side groove percentage to use for a uniform crack front propagation which found a 10% total side groove to be the best percentage. The study showed that for creep fatigue crack growth tests the contour integral (Ct)avg correlated the three tests with hold times of 60 s better than the stress intensity factor K. The creep crack growth tests showed similar results with the contour integral C* being a better crack tip parameter to characterize the data rather than the stress intensity factor K. The creep crack growth tests behaved in a creep ductile manner according to the load line displacement ratio and the non-dimensional crack velocity analyses.