The master failure curve of pipe steels and crack paths in connection with hydrogen embrittlement

Abstract

This paper provides some critical review of the history and state of two elastic fracture mechanics (K and T) and relationship to crack paths. A particular attention is given in the case of hydrogen embrittlement. A fracture toughness transferability curve (Kρc–Tef) has been established for the X52 pipe steels described by a linear relationship where Tef is the average value of T stress over the characteristic length of the fracture process. A mechanism involving influence of the Tef,c-stress on void growth for ductile failure is proposed; the effects of hydrogen on crack paths from the viewpoint of microstructural aspects are disputed.