Vol.3, No2, 2003, pp. 51-64
UDC 620.17:669.14

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