inluence of loading cycle asymmetry and long-term thermal exposure on fatigue crack growth rate in martensitic P91 and P92 steels

Abstract

The paper deals with the effect of different loading cycle asymmetry and long-term thermal exposure on fatigue crack growth rate in P91 and P92 steels used primarily for components in USC powerplants. Testing was performed using C(T) specimens. Fatigue crack growth was measured in II. stage of crack growth described by Paris law from both sides using optical microscope. Loading cycle asymmetry effect was assessed for each steel grade before the thermal exposure and then compared with state after the long-term thermal exposure.