HYDROGEN EMBRITTLEMENT OF PEARLITIC STEELS - PHENOMENOLOGICAL STUDY ON NOTCHED AND PRECRACKED SPECIMENS

In this paper a broad phenomenological study of the hydrogen embrittlement of high strength pearlitic steels is presented. The experimental study includes fracture tests under aggressive environment on cracked and notched samples, with different electrochemical conditions and loading rates. SEM. fractography shows a new microscopic nonconventional- fracture mode: the TTS zone (Tearing Topography Surface) associated with the hydrogen embrittlement phenomenon. There are phenomenological relations between the TTS size and variables such as the electrochemical potential and the maximum stress intensity factor during precracking (for cracked samples), or the time to failure and the geometry (for notched samples).