The paper proposes the method for the assessment of
critical degradation state of heat resistant steels for the components of
power plant complex systems (steam pipelines, boilers or steam turbines).
The experimental investigations of heat resistant
steels were performed by destructive and non-destructive testing. The
destructive testing was based on thermal fatigue, with holding time and
without it. In the second case the attention was paid to the stress
relieved by creep at maximum temperature in the holding time semicycle.
The cumulative fatigue -creep damage of a steam pipeline material was
presented. The non-destructive testing was devoted to the research of the
correlation between metallographic parameter A and the statistically
considered material degradation state.
Keywords: power plant components, creep,
fatigue, heat resistant steel, degradation, damage assessment