Experimental damage analysis of steels after exploitation loading

Abstract

Development of creep damage at elevated temperatures and structural degradation due to plastic deformation at room temperature were assessed using destructive and non-destructive methods in steels commonly applied in power plants (40HNMA, 13HMF and P91). As destructive methods the standard tension tests were carried out after every kind of prestraining. Subsequently, an evolution of the selected tension parameters was taken into account for damage identification. In order to assess a damage development during the creep and plastic deformation the tests for the steels were interrupted for a range of the selected strain magnitudes. The ultrasonic and magnetic techniques were used as the non-destructive methods for damage evaluation. The experimental programme also contained microscopic observations.