Crack initiation behavior of notched specimens on heat resistant steel under service type loading at high temperature

Abstract

ABSTRACT. Cracks at notches deserve special consideration in the design of steam turbine components. This work is addressed to investigate the crack initiation behavior a 10%Cr rotor steel with the help of notched specimens under service-type loading. A significant drifting down of the peak-values of axial deformation under constant amplitude load was observed. Crack initiation was evaluated with the help of the relationship between irreversible deformation energy and cycle number. Further, metallographic examinations were employed to characterize the superposition of creep and fatigue damage mechanisms. Both Neuber-hypothesis and von Mises equivalent strain at notch root were applied for lifetime prediction. Finally, the effectiveness of both methods is validated by comparing with experimental results.KEYWORDS. 10%Cr steel; Notched; Lifetime; Neuber; von Mises.Citation: Cui, L., Wang, P., Crack initiation behavior of notched specimens on heat resistant steel under service type loading at high temperature, Frattura ed Integrità Strutturale, 38 (2016) 26-35.

Creep behavior of V-notched components

“…ue to the complexities of the geometry and loading conditions in modern structural components, it is essential to be able to predict the behavior of components including geometrical discontinuities that generate localized high stress concentration zones [1,7]. They become even more important when, in operating conditions, the component is subjected to very demanding conditions such as high temperature fatigue or creep loading.…”