Creep rupture of circular notched P91-specimens: Influence of heat treatment and notch geometry

Creep failure model of a tempered martensitic stainless steel integrating multiple deformation and damage mechanisms

“…Same conclusions are given by Eggeler et al (1992). On the other hand, there is no difference in the lifetime between NC1.2 and NC0.25 specimens, although the maximum stress triaxiality ratio is much higher in the later specimen.…”

“…This indicates a loss in ductility for values of τ higher than about 1.8. This notch weakening effect has already been observed by Eggeler et al (1992), especially at low stresses.…”

Influence of Heat Treatment in Residual Stresses Generated in P91 Steel-pipe Weld

“…In the as-welded sample, the microstructure of the weld metal is untempered lath martensite (Figure 8a), which explains the high hardness values approaching approximately 450 HV, as shown in Figure 9a and 9b. However, after performing the heat treatment, it shown a microstructure of tempered martensite with high carbide precipitation, as presented in Figure 8b, similar microstructural results are reported by Eggeler et al 20 . The PWHT operation results in a considerable decrease in hardness within the weld metal region (∼260 HV), as shown in Figures 8a and 8b.…”

FY17 Status Report on the Micromechanical Finite Element Modeling of Creep Fracture of Grade 91 Steel

“…• The rate equations for volumetric growth, ! V , reflect fits to finite element results for models containing discrete voids embedded in a creeping solid over a wide range of triaxialities and porosities ( ) 2 / a b , see van der Giessen et al [19,4,5,6,7,8,9,10,13].…”

“…the presence of a notch increases the experimental rupture life. However, there is experimental evidence that for severe notches Grade 91 becomes notch weakening, which could suggest a similar transition to notch-weakening behavior at lower loading stresses [5].…”