ABSTRACT
In this study, using a C(T) specimen for 12Cr steel used for a steam turbine rotor, crack growth tests under creep-fatigue conditions with and without overloading were conducted and the fundamental behaviours of deformation and crack growth were investigated experimentally. As a result, load line displacement was found to be suppressed under overload condition regardless of temperature and stress holding time. Crack initiation life under high temperature and low stress condition with overloading was delayed as compared with no overload condition. However, under low temperature and high stress condition with short stress holding time, crack initiation was accelerated remarkably. Furthermore, although crack growth life under creep-fatigue conditions with overloading was found to be shortened as compared with no overloading, the effect of overloading on crack growth life was decreased with an increase in stress holding time.
Disclosure statement
The authors delare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.